Marshall County Sec 20, T. 1 S, R. 6 E.

South 1/2 sec 20 Measured by M.K. Elias, 1932 Remarks: IV-15

Unit No. Description Thickness ft.   Krider limestone member   35 Limestone 1   Odell shale formation   34 Shale, gray 15.5 33 Shale, red 0.6 32 Shale, green 0.2 31 Shale, red 1.2 30 Shale, green 0.3 29 Shale, red 3.7 28 Shale, green 0.2 27 Shale, light green 3.8 26 Mudstone, soft, massive, green-gray, concretions in upper part 3 25 Limestone, light-gray, cavernous, softer toward base 1.2 24 Limestone, light-gray, softer toward base, with pelycypods and gastropods 1.3 23 Shale, calcareous, with pelycypods and gastropods 2.5   Cresswell ls member and Grant sh member   22 Shale, calcareous, with crinoid and echinoid remains, Linoproductus, Allorisma, few Myalina, bryozoa, Derbya, and Composita 2.5 21 Shale, calcareous, with Derbya and Composita 2.5 20 Limestone to mudstone with large Derbya, Allorisma, and Schizodus 2.5 19 Shale, calcareous, with Dictyoclostus in middle 4.5 18 Shale, calcareous, with crinoid and echinoid remains, Composita, and few Derbya 2.5 17 Shale, gray 1.5   Stovall ls member   16 Flint with large Derbya 0.5   Gage sh formation   15 Shale, calcareous 2.2 14 Mudstone, with numerous large Derbya and few Dictyoclostus 0.8 13 Shale, gray, calcareous, with Derbya and Dictyoclostus americanus 7 12 Shale, red 1.7 11 Shale, green 1.1 10 Shale, red 2.6 9 Shale, green 0.5 8 Shale, red 1.1 7 Shale, green 0.6 6 Shale, red, unpersistent green band in lower part 2.5 5 Shale, green 0.3 4 Shale, red, unpersistent green band in lower part 3.8 3 Shale, green 0.3 2 Shale, red 0.9 1 Shale, green 0.4   (Bottom of eastern trench of the road)