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Stratigraphic Paleontology, continued

Molluscan Faunal Assemblages in Illinoian Deposits

The Crete and Loveland members of the Sanborn formation are the depositional representatives of Illinoian time in Kansas, and since the two members are separable only on a textural basis and are gradational with respect to each other, the molluscan fauna discussed here is a composite assemblage from Crete-Loveland deposits. The occurrence and distribution of 25 kinds of mollusks at 10 localities in the State is shown on Figure 8, and illustrations of a representative assemblage appear on Plate 16.

Figure 8--Occurrence of fossil mollusks in Illinoian deposits at 10 localities in Kansas. An Acrobat PDF version of this figure is available.

Molluscan species	Faunal localities
	SW sec. 35, T. 17 S., R. 13 W., Barton	SW sec. 33, T. 13 S., R. 5 E., Geary	NW sec. 21, T. 24 S., R. 21 W., Hodgeman	NE sec. 5, T. 2 S., R. 7 W., Jewell	NW sec. 2, T. 2 S., R. 9 W., Jewell	SE sec. 13, T. 1 S., R. 9 W., Norton	NW sec. 23, T. 2 S., R. 18 W., Phillips	NW sec. 9, T. 1 S., R. 19 W., Phillips	NW sec. 9, T. 2 S., R. 16 W., Phillips	NW sec. 7, T. 18 S., R. 7 W., Rice
Anodonta sp.
Carychium exiguum (Say)
Carychium perexiguum Baker
Deroceras laeve (Muller)
Discus cronkhitei (Newcomb)
Gastrocopta armifera (Say)
Gastrocopta holzingeri (Sterki)
Gastrocopta tappaniana (C. B. Adams)
Gyraulus similaris (Baker)
Hawaiia minuscula (Binney)
Helicodiscus parallelus (Say)
Helicodiscus singleyanus (Pilsbry)
Helisoma antrosa (Conrad)
Helisoma trivolvis (Say)
Physa anatina Lea
Pupilla blandi Morse
Pupilla muscorum (Linne)
Pupoides albilabris (C. B. Adams)
Retinella electrina (Gould)
Sphaerium solidulum (Prime)
Strobilops sparsicosta Baker
Succinea grosvenori Lea
Vallonia gracilicosta Reinhardt
Vallonia pulchella (Muller)
Vertigo tridentata Wolf

Plate 16--A representative assemblage of mollusks from Illinoian deposits in Kansas. All figures enlarged approximately 5 times natural size. An Acrobat PDF version of this plate is available that shows more detail.

Gastrocopta armifera (Say) Pupilla muscorum (Linne) Pupilla blandi Morse Vertigo tridentata Wolf Gastrocopta tappaniana (C. B. Adams) Gastrocopta holzingeri (Sterki) Vallonia gracilicosta Reinhardt Vallonia pulchella (Müller) Helicodiscus singleyanus (Pilsbry) Deroceras laeve (Müller) Pupoides albilabris (C. B. Adams) Retinella electrina (Gould) HeIicodiscus parallelus (Say) Hawaiia minuscula (Binney) Strobilops sparsicosta Baker Carychium exiguum (Say) Discus cronkhitei (Newcomb) Helisoma antrosa (Conrad) Physa anatina Lea Sphaerium solidulum Prime Gyraulus similaris Baker Helisoma trivolvis (Say) Succinea grosvenori Lea

Typically, Crete sands and gravels grade upward into fluviatile silts, which in turn grade into massive, well-sorted silts judged to be eolian in origin. Almost everywhere in the State where these sediments can be recognized, as well as in Nebraska, Iowa, Illinois, and other surrounding states, the Crete-Loveland sequence has developed in its upper part the Sangamon soil. The Sangamon soil is in fact the most reliable stratigraphic datum available for the recognition of Crete-Loveland deposits, and the fauna under present consideration has been in every case collected only where the Sangamon soil was recognizable as a stratigraphic reference.

The Illinoian assemblage of mollusks is less distinctive than that in Nebraskan, Kansan, or Wisconsinan deposits primarily because no segment of the assemblage is restricted to it. However, with care and a reasonably complete faunule, an Illinoian assemblage can be distinguished from other aggregations of Pleistocene mollusks in Kansas. In general, the Illinoian assemblage is intermediate in character between that in Kansan sediments stratigraphically below it and that in Wisconsinan deposits stratigraphically above it. But as inferred above, the age of the assemblage is based largely on its relation to the Sangamon soil.

In spite of its intermediate character, the Illinoian faunal assemblage has a number of distinctive features worthy of note.

(1) About 14 species of common occurrence in Kansan deposits do not appear in the Illinoian assemblages. None of the genera of branchiate gastropods, such as Amnicola, Pomatiopsis, and Valvata seems to have survived the Yarmouthian interglacial interval in the midcontinent region. Likewise, aquatic pulmonate snails, such as Aplexa, Ferrissia, Menetus, Planorbula, and Promenetus, most species of Gyraulus, and the larger species of Lymnaea, failed to survive the ecological changes that followed the close of deposition of Sappa silts.

(2) Four species, common in Kansan faunules, make their final appearance in the geologic column in Kansas in Illinoian sediments; these include Carychium perexiguum, Strobilops sparsicosta, Gyraulus similaris, and Helisoma antrosa. The first two species are extinct, Gyraulus similaris survives in relict populations in montane lakes in Colorado, and Helisoma antrosa, although extinct on the Great Plains, is still a commonly occurring snail in the more humid regions of central and eastern United States.

(3) A number of species, among which may be mentioned Columella alticola and Striatura milium which are relatively common in Wisconsinan loess (Tazewellian zone of the Peoria silt), are not found in Illinoian assemblages. Furthermore, the slug Deroceras aenigma, common in Nebraskan and Kansan faunas, is replaced in Illinoian molluscan assemblages by Deroceras laeve.

The small number of localities from which molluscan assemblages of Illinoian age are reported here is no indication of the extent of Illinoian sediments in the State. At most localities where Illinoian sediments can be recognized, the gravels, sands, or silts are nonfossiliferous. The reason for this is not completely understood, but a number of contributing factors are known. It is not surprising that few instances of fossiliferous Crete sand and gravel are known, because the fragile shells of mollusks cannot survive for long the abrasive action of coarse sediments in transit. In fact, it is remarkable that any examples of fossiliferous Crete materials are known, since there is not a single instance known to us of shells occurring in recognizable faunules in the coarse phases of the Holdrege or Grand Island gravels. Another contributing factor is that generally over the State, while Illinoian sediments are widespread, they exist as relatively thin strata. Not infrequently, the weathering that produced the Sangamon soil has progressed completely through the entire Illinoian sequence, which would have destroyed, of course, any shells previously present. Finally, the climate during Illinoian time may have been unfavorable to mollusks, although this seems unlikely in view of the kinds that are known to be present. The absence of molluscan remains in unleached Loveland loess at a number of localities remains unexplained.

It is difficult to escape the conclusion that a profound change in ecological conditions in the Great Plains occurred during or at the close of the Yarmouthian interglacial interval, or at the beginning of the Illinoian cycle of erosion and deposition. Wholesale extinction of great populations of branchiate and other gastropods adapted to life in permanent water, which thrived in western Kansas in late Kansan and early Yarmouthian time, is indicative of a less humid environment, or at least of a marked decline in the prevalence of permanent ponds and lakes of clear water in the Great Plains region. The assemblage of aquatic gastropods in late Kansan silt, the prevalence in them of zygospores of some Chara-like alga, and abundance at many exposures of the valves of ostracods all point toward an environment of permanent slow-flowing or ponded water, without excessive siltation, and perhaps with an average temperature somewhat below that prevalent in the same region today or in Illinoian time. By contrast, the aquatic gastropods in Illinoian deposits indicate an environment of ephemeral ponds and silt-laden streams. Anodonta, a lammellibranch pelecypod, and the pulmonate gastropods Helisoma trivolvis and Physa anatina, as well as the little clam Sphaerium solidulum, are all animals capable of living in heavily silted ponds or streams, and capable also of surviving considerable periods without open water. Gyraulus similaris probably was limited to spring-fed ponds or other cooler and clearer waters.

With the exception of Strobilops sparsicosta, which probably lived in or near woodlands, the terrestrial fauna associated with Illinoian deposits is adapted for life in prairies, meadows, or perhaps woodland borders or in small areas of shrubs. Gastrocopta armifera, Hawaiia minuscula, and Pupoides albilabris live in the prairies of western Kansas today, and survive periods of great aridity. Pupilla muscorum, however, and Retinella electrina, Carychium perexiguum, C. exiguum, Helicodiscus singleyanus, Vallonia gracilicosta, Vertigo tridentata, and others are absent from the living molluscan fauna in the Great Plains, so it must be conceded that in Illinoian time ecological conditions were somewhat more favorable toward mollusks than those prevalent today. Certainly the contrast between ecological conditions in Illinoian time and Kansan as well as Nebraskan time was much greater than that between Illinoian and modern time, and we judge that climatic conditions in Kansas during the Illinoian Age were not significantly different than present-day conditions, except for slightly greater rainfall and greater and more widespread sedimentation. It seems, for example, that the ecological situation in Norton or Phillips County in Illinoian time might have been not unlike that in Dickinson or Marion County today.

Molluscan Faunal Assemblages in Wisconsinan Deposits

The molluscan faunal assemblage associated with Wisconsinan sediments has been previously treated by Frye and A. B. Leonard (1951), and by A. B. Leonard (1951, 1952). In the present report, the Wisconsinan molluscan fauna is divided into pre- and post-Bradyan assemblages; the occurrence and distribution of 28 kinds of mollusks from pre-Bradyan Wisconsinan silts at 137 localities is shown on Figure 9, and illustrations of a representative assemblage appear on Plate 17. The occurrence and distribution of 16 species of mollusks at 27 localities where post-Bradyan Wisconsinan deposits have been studied is shown on Figure 10, while a representative assemblage of these mollusks is illustrated on Plate 18.

Figure 9--Occurrence of fossil mollusks in pre-Bradyan Wisconsinan deposits at 137 localities in Kansas. Asterisk in location indicates collection from hand auger samples. An Acrobat PDF version of this figure is available.

Molluscan species	Faunal localities
	SW sec. 30, T. 3 S., R. 38 W., Cheyenne	SE sec. 28, T. 3 S., R. 39 W., Cheyenne	SE sec. 17, T. 1 S., R. 41 W., Cheyenne	SE sec. 16, T. 1 S., R. 42 W., Cheyenne	NW sec. 6, T. 30 S., R. 23 W., Clark	NW sec. 20, T. 33 S., R. 23 W., Clark	NE sec. 26, T. 33 S., R. 24 W., Clark	NW sec. 31, T. 5 S., R. 3 W., Cloud	NE sec. 3, T. 3 S., R. 27 W., Decatur	NE sec. 6, T. 3 S., R. 27 W., Decatur	NW sec. 35, T. 3 S., R. 27 W., Decatur	SW sec. 23, T. 4 S., R. 27 W., Decatur	SW sec. 26, T. 4 S., R. 27 W., Decatur	SW sec. 7, T. 5 S., R. 27 W., Decatur
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NE sec. 1, T. 3 S., R. 28 W., Decatur	NW sec. 23, T. 5 S., R. 28 W., Decatur	NE sec. 14, T. 5 S., R. 29 W., Decatur	SE sec. 6, T. 2 S., R. 20 E., Doniphan	NE sec. 8, T. 1 S., R. 19 E., Doniphan	SW sec. 29, T. 15 S., R. 18 W., Ellis	SW sec. 18, T. 14 S., R. 19 W., Ellis	SW sec. 24, T 21 S., R. 29 W., Finney	NE sec. 34, T. 22 S., R. 30 W., Finney	SE sec. 4, T. 24 S., R. 32 W., Finney	SW sec. 9, T. 24 S., R. 32 W., Finney	NW sec. 16, T. 29 S., R. 24 W., Ford	NE sec. 2, T. 27 S., R. 22 W., Ford	NE sec. 35, T. 15 S., R. 27 W., Gove
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	SW sec. 36, T. 14 S., R. 29 W., Gove	SW sec. 23, T. 9 S., R. 21 W., Graham	NE sec. 28, T. 9 S., R. 22 W., Graham	SE sec. 28, T. 27 S., R. 35 W., Grant	*NE sec. 1, T. 25 S., R. 29 W., Gray	NW sec. 9, T. 16 S., R. 40 W., Greeley	*NW sec. 19, T. 21 S., R. 40 W., Hamilton	SE sec. 12, T. 25 S., R. 41 W., Hamilton	SW sec. 36, T. 25 S., R. 41 W., Hamilton	SE sec. 35, T. 35 S., R. 8 W., Harper	NW sec. 3, T. 28 S., R. 32 W., Haskell	NE sec. 22, T. 30 S., R. 34 W., Haskell	NE sec. 27, T. 23 S., R. 22 W., Hodgeman	NW sec. 26, T. 23 S., R. 25 W., Hodgeman
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NE sec. 4, T. 1 S., R. 7 W., Jewell	SW sec. 19, T. 5 S., R. 8 W., Jewell	*NW sec. 31, T. 23 S., R. 38 W., Kearny	NW sec. 3, T. 28 S., R. 9 W., Kingman	SW sec. 18, T. 16 S., R. 28 W., Lane	NW sec. 7, T. 20 S., R. 28 W., Lane	SE sec. 29, T. 20 S., R. 28 W., Lane	SW sec. 2, T. 16 S., R. 29 W., Lane	NW sec. 3, T. 16 S., R. 29 W., Lane	NE sec. 15, T. 16 S., R. 29 W., Lane	SE sec. 15, T. 16 S., R. 30 W, Lane	*NE sec. 17, T. 17 S., R. 30 W., Lane	SE sec. 27, T. 11 S., R. 32 W., Logan	NW sec. 13, T. 12 S., R. 32 W., Logan
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	SE sec. 3, T. 14 S., R. 32 W., Logan	NW sec. 27, T. 15 S., R. 32 W., Logan	NE sec. 2, T. 14 S., R. 35 W., Logan	NE sec. 9, T. 15 S., R. 35 W., Logan	SE sec. 3, T. 11 S., R. 26 W., Logan	NE sec. 32, T. 12 S., R. 37 W., Logan	NE sec. 8, T. 33 S., R. 27 W., Meade	NE sec. 11, T. 30 S., R. 28 W., Meade	SW sec. 30, T. 31 S., R. 28 W., Meade	NW sec. 6, T. 30 S., R. 30 W., Meade	NW sec. 28, T. 8 S., R. 8 W., Mitchell	NW sec. 10, T. 16 S., R. 22 W., Ness	NE sec. 16, T. 16 S., R. 22 W., Ness	NE sec. 29, T. 16 S., R. 24 W., Ness
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NW sec. 26, T. 2 S., R. 23 W., Norton	NW sec. 11, T. 3 S., R. 23 W., Norton	NE sec. 10, T. 4 S., R. 23 W., Norton	SE sec. 27, T. 4 S., R. 23 W., Norton	SE sec. 13, T. 1 S., R. 24 W., Norton	NE sec. 7, T. 5 S., R. 24 W., Norton	SE sec. 5, T. 2 S., R. 17 W., Phillips	NW sec. 23, T. 2 S., R. 18 W., Phillips	NE sec. 25, T. 1 S., R. 20 W., Phillips	NE sec. 2, T. 3 S., R. 31 W., Rawlins	NW sec. 8, T. 5 S., R. 31 W., Rawlins	SW sec. 2, T. 3 S., R. 33 W.,, Rawlins	NE sec. 9, T. 3 S., R. 33 W., Rawlins	NW sec. 20, T. 4 S., R. 33 W., Rawlins
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NE sec. 8, T. 3 S., R. 34 W., Rawlins	NE sec. 29, T. 3 S., R. 36 W., Rawlins	NW sec. 5, T. 3 S., R. 4 W., Republic	SE sec. 7, T. 10 S., R. 16 W., Rooks	SW sec. 30, T. 9 S., R. 19 W., Rooks	SW sec. 28, T. 17 S., R. 19 W, Rush	SE sec. 17, T. 18 S., R. 31 W., Scott	SE sec. 6, T. 17 S., R. 32 W., Scott	*SW sec. 31, T. 20 S., R. 34 W., Scott	SW sec. 15, T. 6 S., R. 28 W., Sheridan	SW sec. 3, T. 7 S., R. 28 W., Sheridan	SE sec. 28, T. 7 S., R. 28 W., Sheridan	NW sec. 34, T. 8 S., R. 28 W., Sheridan	SW sec. 10, T. 9 S., R. 28 W., Sheridan
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NE sec. 33, T. 10 S., R. 28 W., Sheridan	NW sec. 19, T. 8 S., R. 29 W., Sheridan	NE sec. 13, T. 6 S., R. 30 W., Sheridan	NW sec. 14, T. 6 S., R. 30 W., Sheridan	NW sec. 15, T. 6 S., R. 30 W., Sheridan	NW sec. 31, T. 8 S., R. 30 W., Sheridan	SE sec. 34, T. 10 S., R. 37 W., Sherman	SW sec. 26, T. 10 S., R. 38 W., Sherman	NW sec. 32, T. 7 S., R. 39 W., Sherman	SW sec. 36, T. 6 S., R. 39 W., Sherman	SW sec. 20, T. 7 S., R. 40 W., Sherman	SE sec. 28, T. 1 S., R. 13 W., Smith	SW sec. 11, T. 27 S., R. 39 W., Stanton	NE sec. 2, T. 29 S., R. 40 W., Stanton
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NW sec. 12, T. 28 S., R. 41 W., Stanton	SE sec. 25, T. 29 S., R. 41 W., Stanton	SE sec. 21, T. 7 S., R. 31 W., Thomas	NE sec. 27, T. 7 S., R. 31 W., Thomas	NW sec. 10, T. 8 S., R. 32 W., Thomas	NE sec. 17, T. 8 S., R. 32 W., Thomas	NW sec. 31, T. 7 S., R. 33 W., Thomas	NW sec. 18, T. 9 S., R. 33 W., Thomas	SE sec. 27, T. 10 S., R. 33 W., Thomas	NW sec. 8, T. 8 S., R. 35 W., Thomas	SW sec. 8, T. 8 S., R. 35 W., Thomas	SW sec. 32, T. 7 S., R. 36 W., Thomas	SW sec. 7, T. 8 S., R. 36 W., Thomas	SW sec. 19, T. 8 S., R. 36 W., Thomas
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	NW sec. 3, T. 11 S., R. 23 W., Trego	SW sec. 5, T. 12 S., R. 24 W., Trego	NW sec. 26, T. 15 S., R. 38 W., Wallace	SW sec. 35, T. 11 S., R. 40 W., Wallace	SW sec. 23, T. 12 S., R. 40 W., Wallace	NW sec. 1, T. 15 S., R. 40 W., Wallace	*SE sec. 35, T. 20 S., R. 35 W., Wichita	SW sec. 12, T. 17 S., R. 37 W., Wichita	SE sec. 1, T. 19 S., R. 37 W., Wichita	NE sec. 12, T. 19 S., R. 37 W., Wichita	SE sec. 32, T. 16 S., R. 38 W., Wichita
Gastrocopta holzingeri (Sterki)
Succinea ovalis Say
Gastrocopta armifera (Say)
Hendersonia occulta (Say)
Discus shimeki (Pilsbry)
Succinea grosvenori Lea
Vertigo modesta (Say)
Discus cronkhitei (Newcomb)
Columella alticola (Ingersoll)
Striatura milium (Morse)
Retinella electrina (Gould)
Cionella lubrica (Müller)
Vertigo gouldi coloradensis (Cockerell)
Zonitoides arboreus (Say)

Molluscan species	Faunal localities
	SW sec. 30, T. 3 S., R. 38 W., Cheyenne	SE sec. 28, T. 3 S., R. 39 W., Cheyenne	SE sec. 17, T. 1 S., R. 41 W., Cheyenne	SE sec. 16, T. 1 S., R. 42 W., Cheyenne	NW sec. 6, T. 30 S., R. 23 W., Clark	NW sec. 20, T. 33 S., R. 23 W., Clark	NE sec. 26, T. 33 S., R. 24 W., Clark	NW sec. 31, T. 5 S., R. 3 W., Cloud	NE sec. 3, T. 3 S., R. 27 W., Decatur	NE sec. 6, T. 3 S., R. 27 W., Decatur	NW sec. 35, T. 3 S., R. 27 W., Decatur	SW sec. 23, T. 4 S., R. 27 W., Decatur	SW sec. 26, T. 4 S., R. 27 W., Decatur	SW sec. 7, T. 5 S., R. 27 W., Decatur
Vertigo milium (Gould)
Vertigo tridentata Wolf
Carychium exiguum (Say)
Deroceras laeve (Müller)
Helicodiscus singleyanus (Pilsbry)
Vertigo gouldi paradoxa Sterki
Helicodiscus parallelus (Say)
Euconulus fulvus (Müller)
Hawaiia minuscula (Binney)
Pupilla muscorum (Linne)
Pupilla blandi Morse
Vallonia gracilicosta Reinhardt
Succinea avara Say
Lymnaea parva Lea

Molluscan species	Faunal localities
	NE sec. 1, T. 3 S., R. 28 W., Decatur	NW sec. 23, T. 5 S., R. 28 W., Decatur	NE sec. 14, T. 5 S., R. 29 W., Decatur	SE sec. 6, T. 2 S., R. 20 E., Doniphan	NE sec. 8, T. 1 S., R. 19 E., Doniphan	SW sec. 29, T. 15 S., R. 18 W., Ellis	SW sec. 18, T. 14 S., R. 19 W., Ellis	SW sec. 24, T 21 S., R. 29 W., Finney	NE sec. 34, T. 22 S., R. 30 W., Finney	SE sec. 4, T. 24 S., R. 32 W., Finney	SW sec. 9, T. 24 S., R. 32 W., Finney	NW sec. 16, T. 29 S., R. 24 W., Ford	NE sec. 2, T. 27 S., R. 22 W., Ford	NE sec. 35, T. 15 S., R. 27 W., Gove
Vertigo milium (Gould)
Vertigo tridentata Wolf
Carychium exiguum (Say)
Deroceras laeve (Müller)
Helicodiscus singleyanus (Pilsbry)
Vertigo gouldi paradoxa Sterki
Helicodiscus parallelus (Say)
Euconulus fulvus (Müller)
Hawaiia minuscula (Binney)
Pupilla muscorum (Linne)
Pupilla blandi Morse
Vallonia gracilicosta Reinhardt
Succinea avara Say
Lymnaea parva Lea

Molluscan species	Faunal localities
	SW sec. 36, T. 14 S., R. 29 W., Gove	SW sec. 23, T. 9 S., R. 21 W., Graham	NE sec. 28, T. 9 S., R. 22 W., Graham	SE sec. 28, T. 27 S., R. 35 W., Grant	*NE sec. 1, T. 25 S., R. 29 W., Gray	NW sec. 9, T. 16 S., R. 40 W., Greeley	*NW sec. 19, T. 21 S., R. 40 W., Hamilton	SE sec. 12, T. 25 S., R. 41 W., Hamilton	SW sec. 36, T. 25 S., R. 41 W., Hamilton	SE sec. 35, T. 35 S., R. 8 W., Harper	NW sec. 3, T. 28 S., R. 32 W., Haskell	NE sec. 22, T. 30 S., R. 34 W., Haskell	NE sec. 27, T. 23 S., R. 22 W., Hodgeman	NW sec. 26, T. 23 S., R. 25 W., Hodgeman
Vertigo milium (Gould)
Vertigo tridentata Wolf
Carychium exiguum (Say)
Deroceras laeve (Müller)
Helicodiscus singleyanus (Pilsbry)
Vertigo gouldi paradoxa Sterki
Helicodiscus parallelus (Say)
Euconulus fulvus (Müller)
Hawaiia minuscula (Binney)
Pupilla muscorum (Linne)
Pupilla blandi Morse
Vallonia gracilicosta Reinhardt
Succinea avara Say
Lymnaea parva Lea

Molluscan species	Faunal localities
	NE sec. 4, T. 1 S., R. 7 W., Jewell	SW sec. 19, T. 5 S., R. 8 W., Jewell	*NW sec. 31, T. 23 S., R. 38 W., Kearny	NW sec. 3, T. 28 S., R. 9 W., Kingman	SW sec. 18, T. 16 S., R. 28 W., Lane	NW sec. 7, T. 20 S., R. 28 W., Lane	SE sec. 29, T. 20 S., R. 28 W., Lane	SW sec. 2, T. 16 S., R. 29 W., Lane	NW sec. 3, T. 16 S., R. 29 W., Lane	NE sec. 15, T. 16 S., R. 29 W., Lane	SE sec. 15, T. 16 S., R. 30 W, Lane	*NE sec. 17, T. 17 S., R. 30 W., Lane	SE sec. 27, T. 11 S., R. 32 W., Logan	NW sec. 13, T. 12 S., R. 32 W., Logan
Vertigo milium (Gould)
Vertigo tridentata Wolf
Carychium exiguum (Say)
Deroceras laeve (Müller)
Helicodiscus singleyanus (Pilsbry)
Vertigo gouldi paradoxa Sterki
Helicodiscus parallelus (Say)
Euconulus fulvus (Müller)
Hawaiia minuscula (Binney)
Pupilla muscorum (Linne)
Pupilla blandi Morse
Vallonia gracilicosta Reinhardt
Succinea avara Say
Lymnaea parva Lea

Molluscan species	Faunal localities
	SE sec. 3, T. 14 S., R. 32 W., Logan	NW sec. 27, T. 15 S., R. 32 W., Logan	NE sec. 2, T. 14 S., R. 35 W., Logan	NE sec. 9, T. 15 S., R. 35 W., Logan	SE sec. 3, T. 11 S., R. 26 W., Logan	NE sec. 32, T. 12 S., R. 37 W., Logan	NE sec. 8, T. 33 S., R. 27 W., Meade	NE sec. 11, T. 30 S., R. 28 W., Meade	SW sec. 30, T. 31 S., R. 28 W., Meade	NW sec. 6, T. 30 S., R. 30 W., Meade	NW sec. 28, T. 8 S., R. 8 W., Mitchell	NW sec. 10, T. 16 S., R. 22 W., Ness	NE sec. 16, T. 16 S., R. 22 W., Ness	NE sec. 29, T. 16 S., R. 24 W., Ness
Vertigo milium (Gould)
Vertigo tridentata Wolf
Carychium exiguum (Say)
Deroceras laeve (Müller)
Helicodiscus singleyanus (Pilsbry)
Vertigo gouldi paradoxa Sterki
Helicodiscus parallelus (Say)
Euconulus fulvus (Müller)
Hawaiia minuscula (Binney)
Pupilla muscorum (Linne)
Pupilla blandi Morse
Vallonia gracilicosta Reinhardt
Succinea avara Say
Lymnaea parva Lea

Molluscan species	Faunal localities
	NW sec. 26, T. 2 S., R. 23 W., Norton	NW sec. 11, T. 3 S., R. 23 W., Norton	NE sec. 10, T. 4 S., R. 23 W., Norton	SE sec. 27, T. 4 S., R. 23 W., Norton	SE sec. 13, T. 1 S., R. 24 W., Norton	NE sec. 7, T. 5 S., R. 24 W., Norton	SE sec. 5, T. 2 S., R. 17 W., Phillips	NW sec. 23, T. 2 S., R. 18 W., Phillips	NE sec. 25, T. 1 S., R. 20 W., Phillips	NE sec. 2, T. 3 S., R. 31 W., Rawlins	NW sec. 8, T. 5 S., R. 31 W., Rawlins	SW sec. 2, T. 3 S., R. 33 W.,, Rawlins	NE sec. 9, T. 3 S., R. 33 W., Rawlins	NW sec. 20, T. 4 S., R. 33 W., Rawlins
Vertigo milium (Gould)
Vertigo tridentata Wolf
Carychium exiguum (Say)
Deroceras laeve (Müller)
Helicodiscus singleyanus (Pilsbry)
Vertigo gouldi paradoxa Sterki
Helicodiscus parallelus (Say)
Euconulus fulvus (Müller)
Hawaiia minuscula (Binney)
Pupilla muscorum (Linne)
Pupilla blandi Morse