234 University of Kansas Geological Survey. 
drab limestone in upper one third, Inoceranmus labiatus and charac- 
teristic species, Prionotropis and Woolgarii occasional. 400-500 feet. 
Niobrara.—Drab white limestone, containing /noceramus deformis, 
Inoceranus labiatus, Ostrea congesia. Gray clay and buff siliceo-cal- 
careous Shales with Ostrea congesta and numerous scales. 
CENTRAL AND WEHESTHRN KANSAS SHCTION, Plate XXVII. 
OTR KS INT, IL@eRA, 
Dakota.—Consists of an upper bed of saliferous and gypsiferous 
Shales containing fossils and a thin bed of lignite. Total thickness, 
50 feet. A central group of red and gray sandstone in several 
layers with intervening layers of leaves. Total thickness, 150 feet. 
A lower group of shales, variegated shales, argillaceous, contains 
the following forms: Corbula (?), Trigonarca depressa, Modolia peder- 
nalis, Cardium kansasense, ete. Thickness of group, 300 feet. 
Benton.—A limestone group intercalated with shales. The lower 
layers of limestone compact. Contain sharks’ teeth. The upper 
layers of limestone thicker, white with yellow seam. Intervening 
shale argillaceous. Characteristic fossil, Inoceramus labiatus. Thick- 
ness 100 feet. A central group of variegated shales, argillaceous, 
contain quantities of Ostrea congesta. Thickness 150 feet. An 
upper group of black chaff-like shales, non-fossiliferous, with Sep- 
taria nodules in upper part. Thickness 100 feet. Total thickness of 
group 300 feet. 
Niobrara.—A group of massive white limestone, thickness 50 or 
60 feet. Comparatively soft, hardening somewhat on exposure. 
Almost devoid of fossils except minute organisms of which it is 
composed. An upper bed of chalk of variegated colors. Fossils, in- 
vertebrate and vertebrate, abundant. Ostrea congesta and Inoce- 
ranus deformis abundant, also pyrite nodules. Contains the minute 
organisms of true chalk. Thickness 250 to 300 feet. Total thick- 
ness of group 3590 feet. 
Fort Pierre—Laminated argillaceous shales containing disc-like, 
argillaceous nodules. Noduies containing fossils. Inoceramus (Sp.). 
Shales dark or rusty in color. Shales contain Baculites ovatus, 
Lucina occidentalis, ete. Total thickness 200 feet. 
