from the Comanche to the Dakota Cretaceous. 173 



No. Feet. 



4. Light brown to black sandstone, usually massive with 

 pebbles and large concretions; sometimes cross- 

 bedded and containing clay-ironstone. The Reeder 

 sandstone . . . _ 15-67 



3. Massive sandstone, yellowish to dark brown with occa- 

 sional small concretions of clay-ironstone. It is 

 usually distinctly stratified, but sometimes cross- 

 bedded. The Greenleaf sandstone 25-52 



2. Yellowish to blue clay shale with characteristic clay- 

 ironstone fragments covering the slopes. The Spring 

 Creek clays _ 12-27 



1. Kiowa shales grading into next above 15-15 



A study of these sections, together with the already well- 

 known Comanche series, has led to the following classification 

 -of the Cretaceous rocks of Southwest Kansas : 



III. Dakota Group. 



7. Dakota leaf-bearing sandstone. 

 II. Medicine Beds. 



6. Reeder sandstone. 

 5. Kirby clays. 

 4. Greenleaf sandstone. 

 3. Spring Creek clays. 



I. Comanche Series. 

 2. Kiowa shales. 

 1. Cheyenne sandstone. 



A section of the rocks of the region would be represented 

 as shown in the accompanying figure (p. 174). ; 



The terms Cheyenne sandstone and Kiowa shales are under- 

 stood in the sense as used by Prosser.* The Spring Creek 

 clays are named for Spring creek, a southern tributary to the 

 Medicine river 12 miles west of Belvidere, on which the clays 

 are well exposed. The Greenleaf sandstone is named from the 

 Greenleaf ranch on which the sandstone was first studied, and 

 the Kirby clays from the Kirby (also known as the C. W. or 

 Fullington) ranch on which the clays have a typical exposure. 

 Professor Cragin's term, Reeder sandstone, is used to include 

 all the sandstone between the Kirby clays and the true leaf- 

 bearing Dakota. The entire series of transition beds is included 

 under the term Medicine beds, named from the river near the 

 head of which the beds are best studied. The term Dakota 

 sandstone refers to the true leaf-bearing sandstone. 



The typical exposure of the Medicine beds is on Spring 

 creek, at which point Section III was made, this being the 



*Loc. cit., pp. 112-114. 



