232 University of Kansas Geological Survey. 
Third outcrop: 
4th, Sandstone, 4 feet. 
3d, Shale, red, arenaceous. 
2d, Sandstone, 1 foot. 
Ist, Shale, 22 feet, argillaceous, blue (bottom). 
The stratigraphy of the Upper Dakota is given in the Little Tim- 
ber section. 
CORRELATION OF KANSAS AND COLORADO SECTIONS. 
EASTERN COLORADO SECTION. 
ley Ge Ue, Callllovereus 
Dakota.—Y ellowish gray sandstone, some lower inembers nearly 
white, sonie upper members almost black, surface colors of Jower, 
beautiful tints. Upper layers close textured, the lower beds more 
open. Lower layers scmetimes approach conglomerate in character. 
Intervening shales usually light or dark gray, somewhat arenaceous. 
Contain shreds of vegetable tissue changed to coal. Some shales of 
a greenish brown color. Four fifths of formation sandstone, near 
mountains. Upper sandstone layers thin and alternate with shale. 
Average thickness, 300 feet. | 
Benton.-I. A laminated argillaceous or clayey shale with very 
little admixture of limy or sandy material. Exposure causes to 
form in small flakes. The middle third dark gray, some parts ap- 
parently bituminous, the lower and upper parts medium gray. Rows 
of calcareous concretions found at various levels. Thickness from 
200 to 210 feet. 
tI. Consists of ‘strata of limestone from 3 to 12 inches thick, 
separated by somewhat thicker shale beds. Limestone, pale bluish 
eray, fine grained and compact. Shales have a light gray color, 
laminated, contain more lime than the formations above or below. 
Inoceramus labiatus abundant. Thickness, 25 to 40 feet. 
II. Shale, medium gray, the dominant color, the middle third 
darker. Finely laminated and argillaceous, arenaceous west, pass- 
ing into sandstone, replaced farther east by purplish limestone, with 
*Grove Karl Gilbert: The Underground Water of the Arkansas valley in Hastern 
Colorado. Seventeenth Annual Report of the Director U. S. Geological Survey, 
Washington, 1896. 
