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Description of Species, continued

Pelecypoda

Family Solenomyacidae

Genus SOLENOMYA Lamarck.

Solenomya sp.
(Pl. VIII, figs. 4-4a.)

One large cast appears to belong to this genus, but it is broken along the anterior margin and along the cardinal margin so that determination is very difficult. Shell elongate, subtrapezohedral in outline. Posterior extremity rather narrowly rounded, posterior margin sloping downward and forward from it with a slight appearance of truncation. Ventral margin gently curved to about one-fifth the length of the shell from the anterior extremity, where there is a broad, shallow sinus. Shell convex, the greatest convexity being about the middle. Beaks depressed, not extending beyond the hinge line. Surface crossed by strong concentric wrinkles which become increasingly strong near the margins, and numerous fine radiating striae. Just below the beak there is a vertical, broad, shallow sulcus which gives rise to the sinus of the ventral margin. Anterior adductor scar rather strong, subelliptical in outline, situated about midway between the ventral and cardinal margins and just in front of the sulcus. Posterior adductor scar subcircular, situated near the middle of the shell and close to the cardinal margin.

Horizon and locality. Drum limestone, oolitic member, at Turner, Kan.

Family Grammysiidae

Genus EDMONDIA De Koninck.

Edmondia nebrascensis (Geinitz).
(Pl. VIII, figs. 3-3a.)

1900. Edmondia nebrascensis. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 166, pl. 20, fig. 5.
1911. Edmondia nebrascensis. Mark, Bull. Sci. Lab. Den. Univ., vol. 16, p. 310, pl. 9, fig. 4.

Shell of medium size, equivalve, inequilateral, subquadrate in outline. Dimensions of a typical specimen are: Length, 28 mm.; height, 24 mm.; length of hinge line, 20 mm.; convexity of right valve, 6.2 mm. Anterior, posterior and basal margins nearly straight or subtruncate, broadly rounded on the corners. Posterior side of the shell broader than the anterior so that the basal margin is not parallel to the hinge line. Hinge line nearly straight, becoming a little curved distally to the anterior and posterior margins. Umbones prominent, the greatest convexity being near the middle. Beaks situated about a third of the distance from the middle to the anterior extremity; prominent, extending well beyond the hinge line, directed forwarded and incurved. Surface ornamented by sharp concentric ridges which are separated by furrows three to four times as wide. In well-preserved specimens minute crenulations mark the crests of the ridges and the furrows; and some specimens also show fine concentric lines of growth.

Comparison of the specimens at hand with specimens from the type locality identified as E. nebrascensis Geinitz shows them to be identical in every respect.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner, Muncie and Independence (stations 12, 23), Kan.

Edmondia aspinwallensis Meek.
(Pl. VIII, figs. 1-1a.)

1900. Edmondia aspinwallensis. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 166, pl. 22, figs. 3-ab.

Shell large, inequilateral, equivalve, subovate in outline. The dimensions of one specimen are: Length, 48 mm.; height, 35 mm.; convexity of left valve, 16 mm. Anterior margin sub truncate; basal margin broadly semielliptical; posterior margin rounded. Cardinal margin sloping from the beaks abruptly in front, less abruptly behind, and rounding distally into the posterior and anteror margins. Beaks somewhat prominent, situated in front of the middle of the shell and a little elevated above the hinge line. Umbonal region prominent, flattened, and with the sides rounded and sloping rather abruptly down to the margins of the shell. Surface marked by regular, concentric, sharply elevated ridges separated by furrows from three to five times their width, some of which show faint radiating crenulations or strite. Surface of internal casts marked by heavy, regular concentric undulations. Hinge unknown.

A comparison of this specimen with the type of the species leaves no doubt as to the correctness of the identification.

Horizon and locality. Drum limestone, oolitic member, at Turner, Muncie, Elsmore (station 46) and Independence (station 23), Kan.

Edmondia ? kansasensis Sayre, n. sp.
(Pl. VIII, figs. 5-5a.)

Shell below medium size, subquadrate, equivalve, and inequilateral. Dimensions: Length, 21 mm.; height, 13 mm., convexity of the right valve, 6.5 mm. Anterior and basal margins nearly straight, at slightly more than 90 degrees to each other and with the basal-anterior margin rounded. Posterior margin broadly rounded. Cardinal margin sloping gently posteriorly and curving downward distally into the posterior margin; sloping abruptly downward anteriorly. Umbonal region raised, flattened, sloping gently to the margin posteriorly, more abruptly anteriorly. Beaks compressed, slightly elevated above the hinge, directed forward and situated about one-sixth the length of the shell back from the anterior margin. Surface marked with fine, low, subregular, concentric, rounded ribs.

Two specimens in the collections at hand belong to this species. The general shape, the absence of a lunule and escutcheon, and the fact that the valves are close all round would indicate that this species is a member of the genus Edmondia. Whether this conclusion will be supported by subsequent evidence is, of course, unknown. It resembles E. bellula Girty, but differs from that species in being much larger (about X3) and in having the beaks situated nearer to the anterior extremity. It also resembles E. glabra Meek, but. the beaks are nearer the anterior margin, the basal margin is nearly straight and the posterior margin is not so narowly rounded.

Horizon and locality. Drum limestone, oolitic member, at Turner, Urbana (station 43) and Independence (stations 9, 12, 23), Kan.

Family Nuculidae

Genus NUCULA Lamarck.

Nucula anodontoides Meek.
(Pl. VIII, figs. 8-8a.)

1915. Nucula anodontoides. Girty, U. S. Geol. Surv., Bull. 544, p. 111, pl. 13, figs. 1-5. [available online]

Meek's description: "Shell ovate, ventricose, the greatest convexity being in the umbonal region; posterior side short, faintly subtruncate vertically at the immediate extremity; basal margin semielliptical in outline; cardinal margin nearly straight externally, equaling about half the length of the valves, carinate at the extremities; anterior side rather long, very narrowly rounded in the middle of the extremity, to which point the basal margin rounds up rather gradually, and the anterior dorsal edge slopes obliquely from the edge of the hinge; beaks moderately prominent, convex, incurved without very distinct obliquity and located about halfway between the middle and the posterior side; umbonal slopes, both before and behind, subangular, in con'sequence of the presence of a lunule and escutcheonlike impression, of which that on the anterior or longer side is the larger, being usually continued nearly or quite to the extremity of that side. Surface smooth, or only showing under a magnifier very obscure lines of growth.

"Length of the largest specimen, 0.57 inch; height, 0040 inch; convexity, 0.30 inch. Some of the other specimens are proportionately more convex.

"I have described the shorter side as the posterior of this shell, which, of course, would probably be incorrect if it is not a true Nucula, although I only know from some of the imperfect specimens that it has a coarsely crenate hinge, there can be little doubt that it has an internal ligament, and this differs from Tellinomya and other Paleozoic types that have been separated under other names, since the dorsal margin of the valves can be seen to fit closely all the way along, so as to show no traces of an external ligament. It has not the physiognomy of the typical modern Nuculas, but looks externally like a miniature Anodon. It seems to be closely allied to N. beyrichi V. Schauer, from the Permian of Germany, but is larger, more robust, more nearly smooth, and differs in the lunulelike impressions before and behind the beaks.

"Locality and position. Just below the Mahoning sandstone, Monogalia county, West Virginia Coal Measures."

The shells under observation seem to fit this description very well, although there is no illustration of the type specimen with which to compare them. The lunule and escutcheon are not so pronounced as they apparently were on Meek's specimens. Dimensions of an average specimen: Length, 10 mm.; height, 7 mm.; convexity, 6 mm. The species is about twice the size of N. beyrichi as figured by Meek, its ventral margin has a slightly different curvature, and the beaks are slightly more prominent. It differs from N. parva McChesney in its less prominent beaks and in the fact that the basal margin is subparallel to the hinge line.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Muncie, Kan.

Nucula triangularis Sayre, n. sp.
(Pl. VIII, figs. 6-6c.)

Shell very small, inequilateral, equivalve, subtriangular in outline. The dimensions of a large specimen are: Length, 4 mm.; height, 3.6 mm.; convexity, 2.8 mm. Basal margin nearly straight in the middle and curving narrowly into the posterior and anterior margins; a little longer than the posterior margin, but shorter than the anterior margin. Anterior and posterior margins nearly straight and forming an angle of about 70 degrees, with the cardinal margin represented by a narrowly rounded point. Umbones prominent, flattened; surface of the shell dropping abruptly from the umbones to the margins of the shell. Beaks prominent, close together, extending well beyond the hinge line, directed backward and nearly terminal. Lunule and escutcheon poorly defined, the latter being the longer. Surface nearly smooth, but showing fine concentric lines under the lens; near the margin there are distinct lines of growth, which are especially prominent on some of the older, more gibbous shells.

The outline of this species is so different from any other in the collections that it cannot be confused. Not only is it much smaller than any other, but its triangular outline with nearly straight sides and base, and its highly convex valves serve to differentiate it. It differs from N. wewokana Girty in its comparatively greater height and straight base, and in the much poorer definition of its lunule and escutcheon. Its straight base and triangular shape serve to distinguish it from N. beyrichi V. Schauer.

Horizon and locality. Drum limestone, oolitic member, Muncie and Turner, Kan.

Genus NUCULOPSIS Girty.

Nuculopsis ventricosa (Hall).
(Pl. VIII, figs. 2-2c.)

1915. Nuculopsis ventricosa. Girty, U. S. Geol. Surv., Bull. 544, p. 117, pl. 15, figs. 1-8. [available online]

Shell small, transversely elliptical, the valves strongly convex. The dimensions of a medium-sized individual are: Length, 9 mm.; height, 6 mm.; convexity of both valves, 5 mm. Basal margin curving regularly, except for a slight indentation just behind the. anterior extremity, to the posterior extremity, which is somewhat narrowly rounded. Anterior margin narrowly rounded and shorter than the posterior margin. Cardinal margin with about thq same degree of curvature as the basal; curving abruptly into the anterior, and gently into the posterior margin. Beaks broad, prominent, strongly incurved and directed toward the anterior end of the shell. Lunule poorly defined, forming a slight concavity just below the beaks. Escutcheon scarcely distinguishable. Ligamental grooves present, but only slightly defined. The surface of the shell is nearly smooth, but close examination reveals the presence of faint concentric lines, the larger shells showing pronounced lines of growth.

The examples of this shell under observation are somewhat smaller than most of the specimens previously described, and they differ from them in having the anterior extremity a little more broadly rounded, and extended farther, but careful comparison with specimens from other localities suggests that these differences are due to a difference in the stage of growth. These Kansas specimens also seem to be slightly dwarfed.

Horizon and locality. Drum limestone, oolitic member, Turner and Muncie, Kan,

Family Ledidae

Genus LEDA Schumacher.

Leda bellistriata Stevens.
(Pl. VIII, figs. 7-7c.)

1915. Leda bellistriata. Girty, U. S. Geol. Surv., Bull. 544, p, 122, pl. 14, figs. 1-9a. [available online]

Shell small, longer than high, fairly convex and quite attenuate. The dimensions of an average-sized specimen are: Length, 8 mm.; height, 4.5 mm.; convexity, 3.5 mm. Anterior margin regularly rounded and passing into the basal margin, which is semielliptical in outline near the front, but becomes straight or slightly concave near the posterior extremity. Posterior extremity subangular. Cardinal margin concave posteriorly, anteriorly convex and rounding into the anterior margin. Umbonal ridge well defined; umbones most prominent just below the beaks. Beaks prominent, close together, extending well beyond the hinge line, directed backward, and situated just in front of the middle of the shell. Escutcheon well defined, nearly flat or with a slight concavity between the umbonal ridge and the hinge, and extending to the posterior extremity. Lunule poorly defined. Posterior portion attenuated, extremity slightly gaping. Anterior extremity slightly gaping. Surface ornamented with fine, regular, concentric lines which become obsolete on the posterior umbonal ridges.

This little shell agrees very well with specimens previously described. The umbonal ridge seems to be a little more strongly downcurved, the cardinal margin is hardly visible from the side, and in some specimens the basal margin seems to be a little more strongly curved. It differs from L. arata Hall in the evenness and fineness of the surface ornamentation, in the curvature of both the umbonal ridge and the ventral margin, as well as in its small size. It is much less attenuate then L. meekana and the beaks are nearer to the middle.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Independence (station 23), Kan.

Genus YOLDIA Moller.

Yoldia glabra Beede and Rogers.
(Pl. IX, figs. 1-3.)

1899. Yoldia glabra. Beede and Rogers, Kan. Univ. Quart., vol. 8, No. 3, p. 133, pl. 34, figs. 4a-4b.)
1900. Yoldia glabra. Beede, Kan. Univ. Geol. Surv., vol. 6, p. 153, pl. 21, figs. 4a-4b.
1915. Yoldia glabra. Girty, U. S. Geol. Surv., Bull. 544, p. 126, pl. 13, figs. 9-15. [available online]

Shell much compressed, very thin, transversely elongate and nearly twice as long as high; widest part of the shell a little in advance of the middle. Anterior extremity somewhat narrowly rounded; posterior extremity very narrowly rounded; ventral margin broadly semi elliptical; cardinal margin convex in front of the beaks, concave behind them, but becoming nearly straight before the posterior extremity is reached. Hinge line nearly straight. Escutcheon narrow, lancelike, and poorly defined. Greatest convexity near the middle, from which the sides slope gently to the margins. Beaks situated slightly in front of the middle, depressed, incurved and directed backward. Surface ornamented by fine regular concentric lines, which become obsolete at the cardinal margins.

Most of the shells of this species are broken so that it is not possible to give dimensions of mature forms. A small, nearly complete shell gives the following dimensions: Length, 14 mm.; height, 7.5 mm.; convexity, 2 mm. (right valve).

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Cherryvale (station 40), Kan.

Family Parallelodontidae

Genus PARALLELODON Meek.

Parallelodon sangamonensis (Worthen).
(Pl. IX, figs. 17-17a.)

1916. Parallelodon sangamonensis. Mather, Bull, Sci. Lab. Den. Univ., vol. 18, p. 214.

Shell rather large, transversely elongate, equivalve, inequilateral. Dimensions of a large individual are: Length, 40 mm.; length of hinge line, 34 mm.; height, 18 mm.; convexity, 8 mm. The anterior margin meets the hinge at nearly right angles, extends downward and curves backward into the ventral margin which is somewhat sinuous near the middle. Posterior margin obliquely truncated so as to meet the hinge at an oblique angle; posterior extremity narrowly rounded. Hinge line straight, subparallel to the ventral margin but diverging from it slightly from front to back, and about seven-eighths as long as the entire shell. Beak depressed, incurved, directed forward, extending above the hinge line, and situated about one-fifth the length of the shell behind the anterior margin. Area above the umbonal ridge depressed, subalate. On the umbonal region, a broad shallow depression extends from near the beaks backward and downward to the margin of the shell, causing a slight sulcus in the outline, and some specimens show a second less oblique depression in front of this. Surface of the shell marked by radiating ribs, of which there are six or seven above the umbonal ridge, where they are broadest and strongest, and about twenty-nine on the remainder of the shell. On the umbones the radiating ribs are nearly obsolete, but near the margins they are strong except in the middle portion.

These specimens differ from P. sangamonensis Worthen in their smaller size, in the possession of two constrictions in many cases and in the lack of striations on the anterior portion of the shell, where rather strong ribs are observed instead. They differ from P. striata (Schloth) in the straighter ventral margin and in the obsolete area in the middle portion of the shell.

Horizon and locality. Drum limestone, oolitic member, at Turner, Cherryvale (station 40) and Independence (stations 12, 23), Kan.

Parallelodon kansasensis Sayre, n. sp.
(Pl. IX, figs. 4-7.)

Shell small, subquadrate, inequilateral, equivalve, and somewhat convex. Dimensions of a rather large specimen: Length, 23 mm.; height, 10 mm.; length of hinge line, 19 mm.; convexity of left valve, 4.5 mm. Hinge line straight, a little shorter than the greatest length of the valve, extending to the anterior extremity, from which the anterior margin extends downward and curves backward into the ventral margin, which is subparallel to the hinge line and is sometimes faintly sinuous near the middle. Posterior margin truncated obliquely so as to meet the hinge line at an oblique angle; posterior extremity narrowly rounded. Beaks placed about one-fourth of the length of the shell behind the anterior extremity, extending beyond the hinge line, flattened, incurved and directed obliquely forward. Umbonal region marked by a broad depression which extends obliquely backward from the beak and sometimes causes a faint sulcus in the ventral margin. Umbonal ridge rounded, directed obliquely backward from the beak to the posterior extremity. Above the umbonal ridge the shell is depressed to the hinge line. Surface marked with irregular, concentric lines of growth which are of variable strength and sometimes attain the prominence of low, rounded ridges. Portion above the umbonal ridge marked with radiating striae, which are, in some cases, found also upon the umbonal ridge, but do not extend to the rest of the surface. Hinge narrow, bearing six teeth in front and ten behind; those nearest the center are perpendicular, while on each side they become successively more inclined until the outer teeth are subparallel to the hinge line.

This species is closely related to P. tenuistriata Meek, but differs from that species in the absence of radiating striae on the anterior portion of the shell and in the less-pronounced sinus on the umbonal region.

Horizon and locality. Drum limestone, oolitic member, at Turner, Cherryvale (station 40) and Independence (stations 12, 23), Kan.; and Kansas City, Mo.

Family Conocardidae

Genus CONOCARDIUM Bronn.

Conocardium parrishi Worthen.
(Pl. IX, figs. 20-20c.)

1915. Conocardium missourieneis. Girty, Mo. Bureau Geol. and Mines, vol. 13, 2d ser., p. 353, pl. 28, figs. 3-3c.

Shell small, equivalve, in equilateral, length slightly greater than height. Posterior margin slightly sinuous and somewhat longer than the anterior; hinge line straight. Umbones prominent and sharp, with the sides sloping down to the margins rather more abruptly in front than behind. Beaks small, situated in front of the middle, extending beyond the cardinal margin and apparently anchylosed. Cardinal margin smooth except for fine concentric striae and raised above the hinge line so as to form with it a V-shaped trough. Shell widely gaping behind and extended in front into a tubelike rostrum, which is slightly inclined upward from the end of the hinge. Anterior portion of the shell marked by eight strong, angular, radiating costae, which increase by bifurcation so that only six of them reach the cardinal margin. Posterior portion marked by about thirteen radiating costae, separated by angular furrows as on the anterior portion; but these are crossed by numerous lirae which give this portion of the shell a reticulated appearance. Dimensions: Height, 7 mm.; length, 11 mm.; convexity, 5,5 mm.; length of rostrum, 3 mm.

This group of fossils agrees with C. parrishi Worthen in every respect save the reticulation of the posterior portion of the shell, of which he makes no mention. In his figure, however, these are indicated. These fossils also agree with C. missouriensis Girty, some specimens showing the nodes which he mentions on the umbonal ridge, while others lack any indication of nodes. All three are from the same locality and the same horizon. Many of the fossils found in the oolitic member of the Drum limestone are coated with varying thicknesses of hard calcium carbonate, which may obscure the markings and make determination difficult. It seems probable therefore, that they are identical.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo., Independence (station 23), Kan.

Family Pteriidae

Genus PTERIA Scopoli.

Pteria longa (Geinitz).
(Pl. IX, figs. 13-14.)

1900. Pteria longa. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 125, pl. 16, fig. 4.

Shell small, elongate, convex and obliquely alate. Shell elongate, more or less arcuate, the umbo curving from the beak obliquely backward and downward to the posterior extremity. Anterior extremity narrowly rounded. Ventral margin curving, with a pronounced sulcus about one-third the distance from the anterior extremity. Posterior extremity narrowly rounded. Cardinal margin slightly curved, parallel with the ventral margin, and separated from the ear by a deep sinus. Hinge line, equaling about two-thirds the length of the oblique body portion of the valve, provided with a marginal ridge which is much produced into a long, pointed ear posteriorly. Anterior ear much shorter and broader, somewhat pointed and only slightly convex. Beaks very convex, pointed, and extending beyond the hinge line, placed one-fourth to one-fifth the length of the hinge behind the anterior extremity. Umbo prominent, with the sides of the shell dropping abruptly to the cardinal margin and rounding downward to the ventral margin. Dimensions: Greatest length, 15 mm.; height, 7 mm.; length of hinge line, 12 mm.

Only one of the fossils in this group is of normal size. This is a cast of the left valve. There are, however, a number of smaller specimens which are proportionally longer and thinner, and lack the pronounced sinus of the larger shell. These are referred to the same species.

Horizon and locality. Drum limestone; Oolitic member, at Kansas City, Mo.; Turner and Independence (stations 12, 23), Kan.

Pteria welleri Sayre, n. sp.
(Pl. IX, figs. 15-16.)

Shell small, elongate, obliquely alate. Hinge line straight, equaling about half the length of the oblique body portion of the shell. Anterior margin truncate, meeting the hinge at an angle of nearly 90 degrees. Posterior margin narrowly rounded; cardinal margin straight; ventral margin gently convex and, except for a slight sinus about one-fourth the distance from the anterior margin, subparallel to the cardinal margin, and oblique to the hinge line. Ears small; posterior ear longer than the anterior, rounded distally, flattened and separated from the body by a shallow sinus; anterior ear small, flattened, triangular, depressed, and set off from the body by the abrupt rise of the umbo. Umbo strongly convex, the shell dropping abruptly from it to the cardinal margin and curving to the ventral margin. Umbo crossed by a broad, shallow sulcus extending from near the beak in a direction almost perpendicular to the hinge line, to the margin where it causes a slight sinus in the outline. Beak prominent, extending beyond the hinge line and directed forward. Surface marked by fine, irregular, concentric lines of growth. In the sulcus and parallel to it is a strong ridge which extends nearly to the hinge. Behind the lower half of this ridge and perpendicular to it, but never touching it, are six or seven, sometimes less, parallel ridges separated by furrows of about equal width, and which are equal in length to about one-tenth of the shell, while in front of it there are two to three ridges similar to those behind. On the posterior wing, convex lines of growth are rather pronounced, and are crossed by two or three radiating lines which extend backward from the beak, and give it a very pretty reticulated appearance. Dimensions: Height perpendicular to the hinge, 3.5 mm.; length, 8 mm.; length of hinge line, 5 mm.; convexity, 1.5 mm.

This species is similar to P. sulcata Geinitz in some respects, but differs from it in being much smaller, more elongate, with a shorter posterior ear, and in having only one ridge or wrinkle across the umbo. Doctor Weller had in his collections from the Chester series several shells which were very similar in appearance and in size.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Independence (station 12), Kan.

Genus MONOPTERIA Meek.

Monopteria marian White.
(Pl. IX, figs. 18-19a.)

1900. Limopteria marian. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 128, pl. 16, figs. 5-5c.

Shell convex, alate, obliquely elongated, and pointed on the posterior extremity. The dimensions of a rather small individual are: Height, 24 mm.; length, about 40 mm.; length of hinge, about 25 mm.; convexity, 10 mm. (the posterior end of the body and the wing are broken off slightly). Posterior ear depressed nearly fiat, attenuate and separated from the shell by a deep, narrowly rounded U-shaped sinus. Cardinal margin straight, subparallel to the hinge line; posterior extremity narrowly rounded; ventral margin extending forward in a nearly straight line to about the middle of the shell, from which point it is regularly curved to the lunular area; anterior margin obliquely truncate. Umbonal ridge prominent, curved; the shell sloping abruptly from it on the posterior cardinal side, and on the anterior side, gently at first, but with increasing curve to the anterior and basal margins. Beak prominent but not extending appreciably beyond the hinge line. Hinge line straight. The surface is marked by concentric lines and occasional lamellae of growth which are about parallel to the outline of the shell. The beak is slightly behind the anterior extremity of the shell. Lunule deep and sharply defined.

This shell varies in length and in the width of the body of the shell. It differs from M. gibbosa in having a longer spine, considerably less height, and less curvature to the anteroventral margin. The umbo is more angular than in M. longispina, and the form is more slender.

Horizon and locality. Drum limestone, oolitic member, at Turner, Kan., and Kansas City, Mo.

Monopteria longispina (Cox).
(Pl. IX, figs. 8-9.)

1900. Limopteria longispina. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 127, pl. 16, fig. 6.

Shell large, oblique, slender, alate, and nearly equivalve. Dimensions of a rather small specimen: Length, 39 mm.; height, 28 mm.; length of hinge, 21 mm.; convexity of left. valve; 9 mm. Shell wide anteriorly tapering to a rather narrowly rounded posterior extremity. Basal margin straight from the posterior extremity to a point directly below or slightly behind the beak; then curving upward to the anterior margin, which is nearly perpendicular to the hinge line. Anterior margin obliquely truncated above by the lunule, which is slightly concave in outline. Hinge line straight, equaling nearly three-fourths the total length of the shell. Posterior ear well developed, depressed, narrowly rounded posteriorly, and separated from the body of the shell by a deep U-shaped sinus. Umbo a strong, prominent, rounded, backward-curving ridge from which the sides of the shell drop abruptly to the margin above, while below they are slightly depressed, but extend nearly parallel to the plane of the shell and curve abruptly downward near the anterior and basal margins. Beak prominent, extending well beyond the hinge line, directed forward, incurved and situated about one-fourth the length of the shell behind the anterior extremity. Lunule subelliptical, deep, concave, and very pronounced. Surface marked by fine concentric lines of growth, which become rather coarse near the margins.

The extreme prominence of the beak is one of the outstanding characteristics of this species; this, with the relatively greater height, will serve to distinguish it from M. marian.

Horizon and locality. Drum limestone, oolitic member, at Turner and Elsmore (station 46), Kan.

Genus PSEUDOMONOTIS Beyrich.

Pseudomonotis hawni (Meek and Hayden).
(Pl. X, figs. 1-2.)

1909. Pseudomonotis hawni. Girty, U. S. Geol. Surv., Bull. 389, p. 79, pl. 9, fig. 4. [available online]

Meek and Hayden's description: "Shell subcircular, or subovate; hinge straight, equaling about half the length of the valves; beaks subcentral, short, not oblique; ears nearly obsolete; base rounded; anteroventral and posteroventral margins rounded, the latter being somewhat more rounded than the other. Left valve convex; anterior margin sometimes slightly sinuous near the hinge above; posterior margin intersecting the hinge at an obtuse angle; beak convex, extending but little beyond the hinge line. Right valve nearly or quite fiat; back fiat, not projecting beyond the hinge line; byssal sinus narrow, deep and extending back parallel to the hinge to a point nearly under the beak. Surface of both valves, particularly the left one, ornamented by more or less distinct radiating costae, which are usually separated by a space three or four times their own width, and armed with regularly disposed, vaulted, spinelike prominences, formed apparently from the projecting laminas of growth. Between each two of the principal radiating costae from one to three or four much smaller radiating ribs or lines are usually seen, crossed by obscure concentric markings. Hinge and muscular impressions unknown. Length, 1.47 inches; height, 1.42 inches; convexity, about 0.40 inch."

This form is distinguished from others by its subcircular outline and by the character of its radiating costae separated by three to four or less radiating striae.

Horizon and locality. Drum limestone, oolitic member, at Turner, Muncie, Urbana (station 43), Independence (stations 12, 23), Cherryvale (station 40), Kan., and Kansas City, Mo.

Pseudomonotis kansasensis Beede.
(Pl. X, fig. 6-7.)

1915. Pseudomonotis kansasensis. Girty, U. S. Geol. Surv., Bull. 544, p. 129, pl. 17, figs. 4-4a. [available online]

Beede's description: "Shell large, ovate in outline, rather compressed; beak moderately prominent, projecting beyond the hinge, which is nearly straight. Anterior ear small, rounded to meet the hinge, rather flat, the shell rising rather abruptly to the swell of the umbo. Anterior margin slightly sinuate; anteroventral margin broadly rounded to the ventral portion of the shell, where it becomes nearly straight, then rounding more abruptly to the posterior ear, which is also rounded to the hinge. Greatest convexity a trifle below the beak, but it is very slight. The surface is marked by many fine, wavy, radiating striae of uniform size, extending from the beak to the ventral margin; occasionally one striation will be a trifle larger than another on the central portion of the shell, but it soon loses itself, and on old individuals the striae on the ventral border are all about equal. They increase by implantation and are rather sharply defined, separated by troughs from one to three times their own width, and are generally crossed by fine concentric lines or laminae; right valve unknown. Height, 62 mm.; length, 69 mm.; length of hinge, 23 mm.; convexity, 10 mm.

"This species differs from P. hawni in always having small, regular striae and shorter hinge in the large individuals, as well as being a larger species."

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner, Urbana (station 43) and Independence (station 12), Kan.

Pseudomonotis ? robusta Beede?
(Pl. X, fig. 5.)

1899. Pseudomonotis ? robusta. Beede, Kan. Univ. Quart., vol. 8, p. 82, pl. 18, figs. 2-2c.
1900. Pseudomonotis ? robusta. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 133, pl. 14, figs. 2-2c.

Beede's description: "This shell differs from the preceding [P. kansasensis] in being much more convex and arcuate, in having a longer hinge, higher umbo, beak very much more compressed and scarcely distinct from the umbo, not projecting very sensibly above the hinge. The striae are more regular and much fainter, and either very indistinct or absent on at least the upper third of the shell. Both concentric wrinkles and lamellae of growth are distinct. Length, 48 mm.; convexity, 18 mm.; height, 42 mm.; length of hinge, about 28 mm.

"This species differs from P. hawni in being very arcuate, having a plain umbo, and full anterior and posterior outlines, and fine, even striae on the margins. It differs from P. kansasensis in its broad, smooth umbo and indistinct beak, long hinge and more circular outline."

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Independence (stations 12, 23), Kan.

Pseudomonotis equistriata Beede.
(Pl. IX, figs. 10-12.)

1899. Pseudomonotis hawni equistriata. Beede, Kan. Univ. Quart., vol. 8, p. 82, pl. 18, figs. 3-3b.
1900. Pseudomonotis hawni equistriata. Beede, Univ. Geol. Surv. Kan., vol. 6, p, 134, pl. 14, fig. 3-3b.
1903. Pseudomonotis equistriata. Girty, U. S. Geol. Surv., Prof. Paper 16, p. 428, pl. 8, fig. 5. [available online]

Beede's description: "Shell of medium size, ovate in outline, moderately to quite gibbous, a little oblique with respect to the hinge; beak moderately prominent, extending to or a little beyond the hinge, which is about half the length of the shell and somewhat arcuate. Umbo quite gibbous. Posterior ear very slightly developed, merging into and forming a slight sinus in the posterior margin; ventral, anteroventral and posteroventral margins regularly rounded; anterior margin sinuate in the upper portion on account of the anterior ear, which is small and round. The surface is marked by fine, somewhat regular, rather wavy striae, which increase by intercalation, each fourth to tenth being usually a little larger than the remainder, though not very conspicuously so. Small lamellae of growth sometimes distinguishable. Some of the striae extend nearly to the beak. The right valve is flat or a little concave; otherwise unknown. Measurements of two specimens: Height, 31 mm., 34 mm.; length, 24 mm., 26 mm.; convexity, 7 mm., 13 mm.; length of hinge, 12 mm., 16 mm. These two specimens represent the extremes of convexity.

"This variety differs from P. hawni in being a shorter shell and a little more convex, having regular striae, and in being a little smaller. P. cf hawni, in the article above referred to, should also be considered as a true member of the species. The species here separated are, I believe, distinct from P. hawni; and this variety is worth varietal distinction, as often shells of these kinds are found in localities where others are absent, and some method of distinguishing the two forms of the species is necessary."

The specimens at hand are somewhat more convex than those figured by Beede.

Horizon and locality. Drum limestone, oolitic member, at Turner and Independence (stations 12, 23), Kan.

Pseudomonotis spinosa Sayre, n. sp.
(Pl. X, figs. 3-4a.)

Shell below medium size, subovate and rather convex. Dimensions of a fairly large specimen: Height, 24 mm.; length, 24 mm.; length of hinge about 7 mm.; convexity, 8.5 mm. Hinge short, straight, and slightly oblique, meeting the anterior margin at an angle slightly greater than 90 degrees. Anterior margin slightly sinuous in the middle and rounding into the basal margin. Basal margin regularly arched and rounding into the posterior margin, which is somewhat extended to the rear in a regular curve, but becomes straight just a little above the middle of the shell and slants in to the hinge, meeting it at any angle greater than 90 degrees. Ears slightly flattened and not marked off from the shell except by a slight sinuousity. Umbo prominent, rounded, and subcentral; sides sloping more abruptly to the anterior margin than to the posterior. Beak prominent, well demarked, sharp and extending past the hinge. Surface ornamented by three concentric bands: The first, from the beak for a distance of 8 mm., appearing smooth and only marked by very fine growth lines; below this for a distance of 12 mm. the surface is ornamented by regularly arranged, closely spaced, minute spines, and shows only traces of radiating and concentric lines; from this point to the border is a concentric ring on which the shell is folded into numerous short, broad ribs, separated by furrows of a little more than their width. This concentric band is also covered with regularly arranged spines. Right valve unknown.

The outline of this species is variable, as is the convexity; in some cases the ears appear to be better marked than in others, but the three concentric bands, the beak portion of the umbo smooth, the middle portion marked only by spines, and the marginal area marked by plications and spines, are characteristic of the species. In its general outline and in its variability of form this shell appears to be a Pseudomonotis, and it is referred to that genus temporarily. However, a knowledge of the right valve and the interior is necessary before it can be definitely placed.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Independence (stations 12,23), Kan.

Family Myalinidae

Genus MYALINA De Koninck.

Myalina kansasensis Shumard.
(Pl. X, figs. 9-10a.)

1900. Myalina kansasensis. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 140, pl. 16, fig. 11.

Shell subrhomboidal, inequilateral, and somewhat gibbous. The dimensions of a fairly large specimen are: Height from beak to ventral margin, 59 mm.; width perpendicular to the elongation of the shell, 29 mm.; width of hinge line, 33 mm.; convexity, 11.5 mm. Left valve, the cardinal margin forms an angle of about 60 degrees to the anterior margin of the shell; it is straight and makes an angle of about 120 degrees with the posterior margin. Posterior margin straight near the hinge, but becoming more and more rounded until it curves into the rather narrowly rounded basal margin. Anterior margin sinuous, being rounded at the base and becoming concave a little more than half way up to the beak. Umbo prominent; sloping very abruptly to the anterior margin and more gently to the posterior. Beaks terminal, attenuated, extending obliquely forward and slightly twisted and incurved. Surface with strong nearly equidistant concentric, imbricating lamellae, whose free edges are often irregularly crenate. The ligament face is broad, marked with a number of close-set, equidistant, parallel lines which are parallel to the cardinal margin. Right valve a little less convex than the left. Beak sharp, incurved, twisted, and terminal. Surface marked by strong, imbricating, concentric lamellae which show slight traces of crenulations.

This species may be easily distinguished by its crenate lamellae when these are preserved, and by the small angle of the hinge line with the anterior margin.

Horizon and locality. Drum limestone, oolitic member, at Turner, Muncie, Cherryvale (station 40) and Independence (stations 9, 12, 23), Kan.

Myalina (?) swallovi McChesney.
(Pl. X, figs. 8-8b.)

1900. Myalina swallovi. Beede, Univ. Geol. Surv. Kan., vol, 6, pl. 16, p. 137, fig. 7.

Shell of medium size, modioli form, and somewhat gibbous on the umbones. The dimensions of a rather large specimen are: Height perpendicular to the hinge, 24 mm.; length oblique to the hinge, 36 mm.; length of the hinge line, 21 mm.; convexity of right valve, 7 mm.; obliquity, about 40 degrees. Ventral margin somewhat sinuous, bulging below the beak, concave in the middle, and narrowly rounded into the posterior margin. Posterior margin gently and regularly rounded into the cardinal margin, which is slightly arched. Umbonal ridge prominent, nearly straight, but with a slight curvature near the beak; subparallel to the posterior margin, narrowly rounded, with sides of shell sloping gently to the posterior margin, but dropping abruptly to the ventral margin on the lower half of the shell; and in the upper half separated from the bulge by a narrow, shallow sulcus, which extends from the hinge just in front of the beak obliquely backward to the middle of the ventral margin. Beak small, not pronounced, extending but slightly beyond the hinge line, subterminal, slightly twisted and directed forward. Surface ornamented by numerous fine concentric lines which become stronger near the border of the shell. Hinge area marked by one or sometimes two impressed lines which are parallel to the margin. Shell thin.

This species is quite common in the oolitic member of the Drum limestone, and the numerous specimens show some variation in form. The umbonal ridge is more narrowly rounded in some cases than in others, and the sulcus in front of the umbonal ridge is variable in prominence, being hardly discernible in some specimens; while in some specimens the umbonal ridge is more oblique than in others. These variations, however, seem to be conditions of growth, and there can be little doubt as to the correctness of this identification.

Concerning this species Meek says in his Nebraska report: "The cardinal plate, as seen in authentic specimens from Illinois, is quite narrow, and shows only obscure traces of two cartilage furrows. As I have been unable to see any traces of prismatic structure in the shell, there may be some reason for doubting whether this is a true Myalina." According to De Koninck's description of the genus Myalina, it is thick-shelled, with terminal beaks and a broad cardinal plate bearing numerous parallel, impressed lines. The species under discussion is thin-shelled, with a narrow hinge plate bearing one or two impressed lines, and the beaks are not quite terminal. From this evidence Myalina swallovi is not a true member of the genus Myalina, but would appear to be more properly considered a member of the genus Modiola. Muscle scars and pallial lines are not discernible on any of the casts in the collections at hand.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner, Muncie, Cherryvale (station 46), Urbana (station 43) and Independence (stations 9, 12, 23), Kan.

Myalina (?) slocomi Sayre, n. sp.
(Pl. XI, figs. 1-1a.)

Left valve large, convex, oblique-subquadrate in outline, the dimensions of an apparently full-grown specimen being: Height from beak to basal extremity, 67 mm.; length, 33 mm.; length of hinge line, 42 mm.; convexity, 13 mm.; angle between the hinge and the anterior margin, 76 degrees. The outline of this shell in its anterior-basal-posterior outline is U-shaped, the basal margin being subsemicircular, and the anterior and posterior margins being nearly parallel, except for the upper portion of the anterior margin, which is slightly concave. The beak curving forward, subterminal, twisted, and extending slightly beyond the hinge line; hinge line slightly arched. Umbonal ridge rounded and sloping downward rather abruptly on the lower portion of the anterior side, but sloping gently on the posterior side. The reverse of this is true near the beaks due to the twisting of the beak and the bulging of the superior anterior margin. Umbo separated from the margin in the upper portion by a shallow sulcus extending from about the middle of the anterior side obliquely forward toward the hinge, but dying out before reaching it. Surface crossed by numerous fine concentric striae and rather distant imbricating lamellae. Hinge area narrow, with two subparallel grooves at the beak, of which the inner one extends into the valve and becomes obsolete, and the outer one extends for nearly the length of the hinge. Shell thin; interior unknown.

On the exterior, this shell has somewhat the appearance of M. subquadrata. It differs from that species in that the beak is not nearly so elongate anteriorly, in the straightness of the posterior margin, which shows no sign of sinousity, in the narrow hinge area, in being thin-shelled, as well as in its oblique cardinal margin. This shell shows the same general characteristis as Myalina (?) swallovi. It, too, is probably not a true Myalina, but must be placed in some other genus.

Horizon and locality. Drum limestone, oolitic member, at Turner and Independence (stations 12, 23), Kan., and Kansas City, Mo.

Family Trigoniidae

Genus SCHIZODUS King.

Schizodus harii Miller ?
(Pl. XI, figs. 4-4b.)

1892. Schizodus harii, Miller, 17th Rep. Geol. Surv. Ind., p. 701, pl. 20, figs 1-3.

Shell large, subovate, quite convex, equivalve, in equilateral. Anterior margin regularly rounded; ventral margin semielliptical; posterior extremity subangular; posterior margin obliquely truncate so as to meet the hinge line at an angle of about 135 degrees. Beaks prominent, extending beyond the hinge line about one-seventh of the total height of the shell; rounded, incurved, directed forward and located slightly in front of the middle of the shell. Greatest convexity near the middle. Posterior umbonal slope nearly perpendicular to the plane of the valves, and forming with the shell a subangular ridge which extends from the posterior extremity to the beak. Anterior umbonal slope more gentle, but rather abrupt. Surface marked by rather fine concentric lines widely spaced. Anterior and posterior adductor scars subovate, strong and deep; situated on the umbonal slopes, slightly below the hinge line, and rather near the beak. Dimensions of a right valve: Length, 45 rom.; height, 36.5 mm.; convexity, 15 mm.; length of hinge line, 25 mm.

It is with some doubt that this shell is referred to S. Harii. The posterior margin is more clearly truncated than in that species, and the beak appears to be more nearly central. The posterior extremity is more pointed. In this respect the shell resembles S. wheeleri, from which species it differs, however, in the more centrally located beak and less-produced posterior side.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo., and Turner, Kan.

Schizodus trigonalis Sayre, n. sp.
(Pl. XI, figs. 2-2a.)

Shell under medium size, subtriangular and somewhat compressed. Dimensions of a large specimen (left valve) are: Length, 13.8 mm.; height, 12 mm.; convexity, 3.8 mm. Anterior margin sub truncate, rounding into the ventral margin, which is gently arched and at about 90 degrees to the anterior margin. Posterior extremity angular; posterior margin obliquely truncated; hinge line short. Beak somewhat depressed, subcentral, incurved, pointed and extending only a short distance beyond the hinge line. Posterior umbonal ridge prominent and extending from the beak to the posterior extremity; anterior more gently rounded and not so pronounced. Posterior umbonal slope perpendicular to the plane of the shell near the beak, but becoming slanting as the posterior extremity is approached, so that the posterior margin projects beyond the umbonal ridge. Surface almost smooth, but showing, under the magnifier, very fine concentric striae.

This species differs from S. securus Girty in its short hinge line. It resembles S. depressus Worthen from the St. Louis group, but is more convex; the posterior extremity is more sharply angular, and the anterior margin is not so regularly curved.

Horizon and locality. Drum limestone, oolitic member, Muncie, Kan.

Family Pectinidae

Genus AVICULOPECTEN McCoy.

Aviculopecten providencesis (Cox).
(Pl. XII, figs. 1-2.)

1900. Aviculopecten providencesis. Beede, Univ. Gol. Surv. Kan., vol. 6, p. 119, pl. 13, fig. 2.

Shell large, subcircular, with the height equal to the width, rather convex. Dimensions of a large specimen are: Height, 71 mm.; greatest length, 71 mm.; length of hinge line, 41 mm.; convexity, 15 mm.; angle between the sides of the umbo, 87 degrees. Left valve large and rather convex, the greatest convexity being near the beak. Ventral margin regularly rounded from below the anterior ear to the posterior extremity, from which point it is straight, except for the ears, to the beak. The umbo is pronounced, the beak extending very slightly beyond the hinge line. Ears are depressed and subequal, the posterior one being a little the larger, and both being defined from the shell by the abrupt swell of the umbo. The anterior ear is separated from the body of the shell by a sharp, deep sinus, and is rounded upward, passing into the hinge line at an angle of about 90 degrees. The posterior ear is separated from the shell by a rounded, shallow sinus and terminates in a point. Surface of the shell ornamented by a number of radiating costae made up of from two to five or six striae, so as to give a fasciculated appearance to the shell. The striae are present on the anterior ear, but only one or two of them are seen on the posterior ear. Crossing the costae are numerous rather fine concentric lamellae, which are difficult to discern on the body of the shell, but show up rather strongly on the ears.

The right valve and the interior of the shell are not known.

This species is easily distinguished by its fasciculated appearance. It resembles A. chesterensis Worthen in its fasciculation, but is a larger shell, more convex, and has larger, less numerous fascicles, and a longer hinge line.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Muncie and Independence (station 9), Kan.

Aviculopecten sculptilis Miller.
(Pl. XI, figs. 9-10.)

1892. Aviculopecten sculptilis, Miller, 17th Rep. Goel. Surv. Ind., p. 702, pl. 20, fig. 5.
1900. Aviculopecten sculptilis. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 122, pl. 13, figs. 3-3b.

Shell rather large, auriculate, subovate exclusive of the ears, inequivalve, height greater than length. Left valve moderately convex. Lateral and ventral margins regularly rounded and tapering to the beak at an angle of about 90 degrees. Beak small, depressed and scarcely extending beyond the hinge line, situated about two-thirds of the way back from the anterior end of the hinge. Ears small, depressed and sharply defined from the swell of the umbo; anterior ear about twice the size of the posterior, and each is separated from the shell by a more or less distinct sinus in the margin. Both ears are marked by well-defined concentric striae and the anterior ear shows faint traces of radiating lines. Surface of the shell marked by fine, regular, concentric lines crossed by equally prominent and closely set radiating lines, which give the shell a beautifully reticulate appearance. Near the borders the enlargement of these lines gives a very rough appearance to the shell. Dimensions: Length, 41 mm.; height, 49 mm.; length of hinge line, 17 mm.; convexity of left valve, 8 mm.

This shell differs from A. hertzeri in being more slender, with a more acute angle at the beak, and is a larger shell.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner and Independence (stations 9, 12, 23), Kan.

Genus DELTOPECTEN Etheridge.

Deltopecten occidentalis (Shumard).
(Pl. XI, figs. 5-8.)

1916. Deltopecten occidentalis, Mather Bull. Sci. Lab. Den. Univ., vol. 18, p. 227.

Shell of medium size, pectenate, subovate, not oblique, inequivalve. Left valve moderately convex, with ears subequal; anterior ear rather sharply defined from the swell of the umbo by a broad groove, rounded at the tip and marked with distinct radiating costae. Posterior ear pointed, flattened, and not so well defined from the umbo, sometimes without radiating costae, but in other cases having them well developed. Both ears separated from the shell below by a rounded, broad sinus, which is deeper on the anterior side than on the posterior. Surface of the shell covered with radiating costae generally of unequal width, of which only the largest extend to the beak, while the others die out at various distances from the beak. Crossing these are numerous fine concentric lines, some of which sometimes form vaulted scales on the costae of the ears, particularly the anterior one, and generally these vaulted projections are well and strongly developed on the posterior costa of the body part of the shell.

Right valve much flatter than the left, but having the same general outline. Beak depressed and hardly distinct from the hinge line. Anterior ear defined from the body of the shell by a sharply angular sinus; posterior ear defined by a broad rounded sinus. Surface of the body of the valve marked by broad, low, radiating costae separated by depressions of less than a quarter of their width and crossed by fine, indistinct concentric lines which extend to the ears, while the radiating costae do not appear on the posterior ear, and only rarely on the anterior. Interior nearly smooth except for narrow, rather widely separated, radiating lines. The muscular area is very obscure on the posterior side of the body of the shell and about two-thirds of the distance from the margin to the beak. A more or less serrate ridge extends along the hinge line. A mature specimen measures: From beak to ventral margin, 28 mm.; length, 23 mm.; length of hinge line, 21 mm.; convexity, 5 mm.; angle of the umbo, 78 degrees.

This species is abundant in the Drum limestone, and in a large number of specimens shows minor variations. Occasionally a slightly oblique specimen is found, the obliquity never being more than 5 degrees. Small specimens appear narrower than more mature ones. The hinge line varies somewhat in length.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Muncie, Turner, Elsmore (station 46), Urbana (station 43), Cherryvale (station 40) and Independence (stations 12, 23), Kan.

Genus ACANTHOPECTEN Girty.

Acanthopecten carboniferus (Stevens).
(Pl. XII, figs. 5-6.)

1915. Acanthopecten carboniferus, Girty, U. S. Geol. Surv., Bull. 544, p. 134, pl. 17, figs. 10-10a. [available online]

Shell a little under medium size, auriculate, inequivalve, and with regularly arranged spines. Left valve convex, subcircular in outline, and with a serrate edge. Posterior ear separated from the valve by a well-defined sinus, and from the swell of the umbo by a rather strong sulcus. The ear is extended and terminates in a point. Anterior ear shorter, more obtuse, and defined from the umbo by a deep angular sulcus. Both ears flattened. Surface of the valve ornamented by fifteen to seventeen distinct, regular, angular plications, separated by furrows of like size, which terminate on the ventral border in short, strong spines. Numerous fine concentric lines may be seen by the aid of a hand lens. At intervals which decrease as the beak is approached, are found laminae of growth which follow the outline of the shell, and provide Ii series of bands of spines on the surface of the shell. Beak prominent, but scarcely extending beyond the hinge line. The right valve is similar in outline to the left, but is much less convex, and the beak is much less prominent. Dimensions: Length, 21 mm.; height, 18 mm.; length of hinge line, 15 mm.; convexity of left valve, 5 mm.

Horizon and locality. Drum limestone, oolitic member, at Kansas City, Mo.; Turner, Muncie, Elsmore (station 46), Urbana (station 43), Cherryvale (station 40) and Independence (station 12), Kan.

Family Pectinidae

Genus STREBLOPTERIA McCoy.

Streblopteria tenuilineata (Meek and Worthen).
(Pl. XI, figs. 3-3a.)

1860. Pecten tenuilineatus, Meek and Worthen, Proc. Acad. Nat. Sci. Phil., p. 452.
1866. Streblopteria ? tenuilineata. Meek and Worthen, Geol. Surv. Ill., vol, 2, p. 334, pl. 26, figs. 9 a-b.
1905. Streblopteria tenuilineatus. Girty, U. S. Geol. Surv., Prof. Paper 16, p. 419. [available online]

Shell small, compressed, thin, subcircular in outline except for the ears. Dimensions of one specimen are: Greatest anteroposterior diameter, 14 mm.; height, 14 mm.; length of hinge line, 7.4; angle between sides of umbo, about 100 degrees.

Right valve compressed, subcircular and thin-shelled, with the anterior side wider than the posterior. From just below the posterior ear the margin is a regular semicircular curve to just below the anterior ear, which is separated from it by a sharp angular sulcus passing obliquely backward to the hinge, which also separates the ear from the umbo. Anterior ear larger than the other, convex, but not equaling the prominence of the umbo, and rounded on its anterior margin. Posterior ear triangular, nearly obsolete, obliquely truncated and compressed, defined by a very slight marginal sinuousity, and not separated from the umbo by a pronounced sulcus. Beak small, pointed, and rather compressed, terminating a little behind the middle of the hinge line and projecting very slightly beyond it. Anterior umbonal slope oblique and more distinct from the ear than the posterior one. Surface appearing smooth to the unaided eye, but with the aid of a lens fine concentric lines of growth may be seen closely spaced over the surface, and occasionally crossed by radiating lines which are even fainter. Anterior ear marked by concentric wrinkles.

One specimen of this species, which is a right valve, is found in the collections.

Horizon and locality. Drum limestone, oolitic member, at Turner, Kan.

Family Limidae

Genus LIMATULA Wood.

Limatula ? fasciculata Girty.
(Pl. XII, figs. 7-8a.)

1911. Limatula ? fasciculata. Girty, New York Acad. Sci. Annals, vol. 21, p. 134.
1916. Limatula ? fasciculata. Girty, U. S. Geol. Surv., Bull. 544, p. 138, pl. 17, figs. 6-7. [available online]

Shell small, oblique, depressed, equivalve. Left valve obliquely subovate. Hinge line short; anterior and posterior margins nearly straight; anterior extremity narrowly rounded; ventral margin gently rounded and curving into the posterior margin. Beak small, depressed and extending slightly beyond the hinge line. Ears small, sloping down from the umbo, not much depressed; anterior ear slightly larger and somewhat more depressed. Ears not separated from the margins of the shell, but sloping gradually into them. Umbo prominent, with sloping sides. Surface of the valve marked by about forty radiating lines which become obsolete on the anterior and posterior margins, and which are grouped into fascicles of three or more lines each, and the fascicles are separated by rounded furrows of about half their width. These are crossed by very fine concentric striae and a few lamellae of growth, which may also be seen upon the ears. Right valve of essentially the same size, outline, and convexity. Although the markings are somewhat obscure, close examination indicates that they are similar to those on the left valve.

Dimensions: Length,5 mm.; height,6 mm.; length of hinge line, 2 mm.; convexity, 1 mm.

This shell is much smaller than L. fasciculatus, but the markings and general shape appear to be identical.

Horizon and locality. Drum limestone, oolitic member, at Turner, Kan.

Family Mytilidae

Genus LITHOPHAGA Lamarck.

Lithophaga subelliptica Sayre, n. sp.
(Pl. XII, figs. 9-9a.)

Shell small, slender, subelliptical, equivalve, convex. The dimensions of a rather large individual are: Length, 11.5 mm.; height perpendicular to the hinge line, 4.5 mm.; convexity, 1.8 mm. Anterior and posterior margins narrowly rounded, the anterior somewhat more narrowly than the posterior; ventral margin nearly straight, arching upward rather slowly distally to the posterior and anterior extremities. Hinge line straight or only slightly arched, equaling about three-fourths the entire length of the shell. Posterodorsal margin sloping obliquely forward, and nearly straight from the posterior extremity to the hinge line, and meeting the latter at only a slight angle. Shell convex, the umbonal region being extended at a slight angle to the hinge line. Beaks compressed, not extending beyond the hinge line and very nearly terminal. Surface of the valve nearly smooth, but fine concentric striae, rather irregular in size, may be noted under the lens. Interior and hinge unknown,

This species resembles L. pertenuis Meek and Worthen, from the Mississippian, in general outline but is a much smaller form, has less prominent beaks, and is more oblique.

Horizon and locality. Drum limestone, oolitic member, at Turner and Muncie, Kan.

Family Pholadellidae

Genus ALLERISMA King.

Allerisma costatum Meek and Worthen.
(Pl. XII, fig. 10.)

1900. Allerisma costatum. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 170, pl. 20, fig. 12.

Shell transversely elongate, equivalve, inequilateral and somewhat under medium size for the genus. The dimensions of a fair-sized shell are: Length, about 40 mm.; height, 15.5 mm.; convexity of right valve, 6 mm. Anterior margin rather short and narrowly rounded; basal margin forming a broad, nearly semielliptical curve; posterior portion compressed and truncated vertically from the base to a little over halfway up, and thence obliquely forward and upward to the cardinal margin. Posterior dorsal region compressed above the umbonal ridge. Hinge line straight, and equaling about two-thirds the entire length of the shell. Beaks convex, directed forward, extending slightly beyond the hinge line, and placed well forward on the shell. Lunule narrow, elongate, and extending from the beak to the anterior margin. Surface ornamented by strongly raised, sharp, angular, concentric costae, which are separated by furrows about three times their width. They extend backward from the lunule, parallel to the margins, to the well-defined umbonal ridge, which extends from the posterior extremity to the beaks. Above the umbonal ridge they become much smaller and their number doubles on the flattened posterior cardinal region. They are crossed by a second ridge, less strong than the first, which extends from the middle of the posterior margin to the beak.

This shell seems to agree closely with Meek's description except that it is a little larger, and not so convex. He makes no mention of the doubling of the number of the costae above the umbonal ridge, nor does he figure it. It is true that here they are less pronounced than below the ridge, but are certainly stronger than mere lines of growth on the lower portion of the area above the umbonal ridge, although above this they become more and more indistinct. In a later paper Meek again describes A. costata, and his figure does not show the truncation of the posterior portion, but simply a rounding of it, and lacks, besides, the second ridge on the depressed superumbonal region. In this figure, however, he shows the costae doubling in number.

Horizon and locality. Drum limestone, oolitic member, at Turner and Independence (stations 12, 23), Kan.

Family Pleurophoridae

Genus PLEUROPHORUS King.

Pleurophorus subcostatus Meek and Worthen.
(Pl. XII, figs. 11-13a.)

1900. Pleurophorus subcostatus. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 161, pl. 20, figs. 11-11b.

Shell of medium size, elongate, moderately convex and equivalve. The dimensions of a fairly large specimen are: Length, 27 mm.; height, 12 mm.; convexity of one valve, 4 mm. Cardinal margin nearly straight and subparallel to the ventral margin, which. is sometimes faintly sinuous along the middle. Posterior and anterior extremities rather narrowly rounded, the former being a little wider than the latter, and sometimes faintly subtruncate. Most convex portion of the shell along the umbonal ridge, which extends obliquely backward from the beak to the posterobasal margin. Beaks small, somewhat compressed, and not extending beyond the cardinal margin, directed forward and situated about one-ninth the length of the shell back from the anterior margin. Surface marked by fine concentric lines of growth and crossed on the posterodorsal region by about three faint radiating costae. On the cardinal margin there is a strong, angular ridge, which marks the outline of a long lancelike escutcheon. Scar of the anterior adductor, subtriangular, deep, pointed above, and strongly defined by a prominent, nearly vertical ridge behind it. A broad, shallow sulcus crosses the umbo obliquely and extends from the beak obliquely backward to about the middle of the ventral margin.

This shell seems to be a little larger than Meek's shell, and the ventral margin makes a little greater angle with the cardinal margin. It is, however, almost certainly the form identified by Girty as P. subcostatus, from the Yeso Formation.

Horizon and locality. Drum limestone, oolitic member, at Turner, Elsmore (station 46), Cherryvale (station 40) and Independence (stations 12, 23), Kan.

Pleurophorus tropidophorus Meek.
(Pl. XII, figs. 14-15.)

1916. Pleurophorus tropidophorus. Mather, Bull. Sci. Lab. Den. Univ., vol. 18, p. 230.

Shell transversely elongate, compressed; length about twice as great as the height. Cardinal margin nearly straight, equaling about two-thirds the length of the valves. Anterior margin sloping abruptly forward from the beaks, rounded below, with the anterior extremity subtruncate and nearly vertical. Ventral margin long, parallel to the cardinal margin, forming a well-defined angle with the posterior margin and rounding upward anteriorly. Posterior extremity truncated vertically; posterocardinal margin truncated oblique to the hinge. Umbo angular, extending obliquely backward from the beak to the posteroventral extremity, while a second carina passes down the middle of the space above the umbonal ridge of each valve. Beaks depressed to the cardinal margin and directed forward, placed about one-fifth the length of the valves behind the anterior margin. Surface marked by distinct, concentric lines of growth, rather irregular in size, which are very strong on the anteroventral portion of the valves, but are less distinct above and behind the umbonal ridge. Shell thin.

The most characteristic features of this species are the increased strength of the lines of growth on the anteroventral portion of the shell, the truncations of the posterior margin, and the strong angulation of the posterior umbonal slope.

Horizon and locality. Drum limestone, oolitic member, at Turner, Cherryvale (station 40) and Independence (stations 9, 12,23), Kan.

Pleurophorus attenuatus Sayre, n. sp.
(Pl. XII, figs. 3-4a.)

Shell of medium size, elongated transversely, equivalve, inequilateral, and moderately convex. The dimensions of a fairly large individual are: Length, 33.5 mm.; height, 11.5 mm.; convexity, 5.5 mm.

Cardinal and ventral margins straight and subparallel, but converging slightly toward the posterior end of the shell. Anterior and posterior margins narrowly rounded; posterior end a little more narrowly rounded. Hinge line equaling about two-thirds the length of the shell, and meeting the narrowly rounded posterior margin with only a slight angle. Umbonal ridge the most convex part of the shell and extending from the beak to the posteroventral extremity as a. gently rounded ridge. Posterocardinal region depressed. Beaks depressed to the cardinal line, and situated near the anterior extremity. A broad, shallow sulcus extends obliquely downward and backward from the beaks to a little in front of the middle of the ventral margin, Surface marked by fine, irregular, concentric lines of growth. On the depressed area above the posterior umbonal ridge may be seen three to four small, more or less pronounced, radiating ridges. Escutcheon well defined, elongate, lance-ovate in form, and extending from the beaks to the posterior extremity of the hinge line. Anterior adductor trigonal-ovate in form and pointed above, deeply impressed and demarked by a strong, nearly perpendicular ridge which lies behind it; situated in front of the beaks and somewhat below them. Posterior adductor scar ovate, somewhat larger than the anterior muscular scar, situated below the posterior end of the hinge. Hinge unknown.

This shell is apparently closely related to P. mexicanus Girty, and also to P. subcostatus Meek: It differs from the former in having the ventral margin straight instead of arched, in being less convex, in having the posterior margin more rounded than truncate, and in being proportionately longer and narrower. It differs from the latter in having a longer, straighter appearance, in lacking the ventral sinuousity, and in being broader on the anterior end instead of the posterior.

Horizon and locality. Drum limestone, oolitic member, at Turner and Independence (stations 9, 12), Kan.

Pleurophorus turnerensis Sayre, n. sp.
(Pl. XII, figs. 16-17a.)

Shell of medium size, transversely elongate, inequilateral, equivalve. Length more than twice the greatest height. Hinge line slightly arched and equaling about two-thirds the greatest length of the shell. Anterocardinal margin set somewhat below the beaks, parallel to the hinge line, and extending beyond the beaks about one-fifth the entire length of the shell. Anterior extremity nearly vertical; anterior margin rounding rapidly into the basal margin, which is straight or slightly sinuous and diverges slightly from the parallel with the cardinal margin posteriorly. Posterior extremity narrowly rounded; posterior margin slightly arched and meeting the hinge line at an angle of about 60 degrees. Convexity moderate, greatest just behind the middle of the shell. Posterior umbonal slope with a distinct ridge which extends from the beaks obliquely backward to the posterior extremity. Beaks depressed on a line with the hinge, and directed forward. Surface marked by fine concentric lines of growth, of which every seventh or eight is stronger than average. Shell thin.

This species is closely related to P. taffi Girty. It is possible that the two will be found identical, although P. turnerensis is smaller, higher in relation to its length, the anterior portion of the shell more extended, and the posterior margin at a greater angle to the hinge line.

Horizon and locality. Drum limestone, oolitic member, at Turner and Independence (stations 12, 23), Kan.

Family Astartidae

Genus CYPRICARDINIA Hall.

Cypricardinia carbonaria Meek.
(Pl. XIII, figs. 1-2a.)

1900. Cypricardinia ? carbonaria. Beede, Univ. Geol. Surv. Kan., vol. 6, p. 164, pl. 20, fig. 16.

Shell small, inequilateral, equivalve, and oblique. The dimensions of a fairly large specimen are: Length, 12 mm.; height from the base to hinge line, 7.5 mm.; convexity of left valve, 3 mm.; length of hinge line, 7 mm. Anterior extremity narrowly rounded. Posterior margin obliquely truncate, meeting the hinge at an obtuse angle. Posterior extremity not so narrowly rounded. Ventral margin nearly straight or only slightly concave near the middle,

oblique to the hinge, and rounding up at the ends. Hinge line straight, forming an acute angle with the ventral margin. Posterior cardinal area compressed and flattened, giving it a subalate appearance. Umbones prominent, rounded and oblique. Beaks oblique, directed forward, incurved, and nearly terminal, broad, and extending beyond the hinge 'line. There is a slight, broad, shallow sulcus at about the middle of the umbonal region, extending obliquely backward and downward from the beaks, and becoming obsolete at the margin. The surface is ornamented by numerous regular, broad, subimbricating, flattened, concentric lamellae, which become closer and finer near the beak. On some specimens there are about nine radiating striae located on the posterior umbonal ridge, and in most cases only touching the outer edges of the lamellae, clearly seen in some cases, but very obscure in others.

These shells are a little narrower at the anterior end than Meek's figures show; and also he makes no mention of the radiating striae. Nevertheless, it appears to be the same species or very closely allied to it, as these characters vary from specimen to specimen.

Horizon and locality. Drum limestone, oolitic member, at Turner, Muncie and Independence (stations 9, 12,23), Kan.; Kansas City, Mo.

Genus ASTARTELLA Hall.

Astartella gurleyi White.
(Pl. XIII, figs. 3-3a.)

1880. Astartella gurleyi. White, Cont. to Inv. Pal., No. 8, p. 166, pl. 42, figs. 6 a-b.

White's description: "Shell small, not very gibbous, subtetrahedral in outline; anterior end truncated from the beaks obliquely downward and forward to about midheight of the shell, where the front is sharply rounded to the somewhat broadly rounded basal margin; posterior margin broadly convex or sometimes almost straight and perpendicular, and adjoining both the basal and dorsal margins by abrupt curves; dorsal margin comparatively short, nearly straight; beaks small; umbones not elevated nor very prominent. An indistinctly defined umbonal ridge extends from each of the umbones to the posterobasal margin, behind which ridge the shell is slightly compressed. Surface marked by concentric furrows, which are separated by sharp linear ridges. Length of an average-sized example, 7 mm.; height from base to beaks, 4.5 mm.

"This species differs from A. vera Hall, from the same formation, in its smaller size, in the slight prominence and want of elevation of the umbones, the greater proportional projection of the front beyond the beaks, and in being wider behind than in front, the reverse being the case with A. vera."

It is with some hesitation that this shell is referred to the species A. gurleyi. It differs from that shell in being larger, and lacks the faint sinuosity behind the beak which that shell shows. Otherwise it is much the same. Dimensions of my shell are: Height, 8 mm.; length, 11 mm. It differs from A. concentrica in having the beaks placed further forward, and in having less coarse striae. A. vera shows similar differences.

Horizon and locality. Drum limestone, oolitic member, Turner, Muncie, Elsmore (station 46) and Independence (stations 12, 23), Kan.

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Kansas Geological Survey, Geology
Placed on web Dec. 27, 2017; originally published June 15, 1930.
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