1897.] DRAKE — THE GEOLOGY OF IXUIAX TERRITOIir. 377 



A section across the group along a line from Adair through 

 Chelsea and Oologah to Pawhuska is as follows : 



FEET. 



1. Coal (Maybery coal ? ) 2 



2. Clay shale 100 



3. Limestone (Oologah limestone ^) 50 



4. Arenaceous clay shale and a little interstrati- 

 fied shaly sandstone 200 



5. Gray limestone , . , . 15 



6. Clay shale 5 



7. Coal ik 



8. Clay shale and sandstone . 50 



9. Limestone 2 



TO. Clay shale 50 



11. Coal 12^ 



12. Clay shale and a little sandstone 150 



13. Sandstone 25 



14. Clay shale 15 



1 5 . Coal (Grady coal ?) li 



Total thickness (approximate) 650 



These three sections [show the Cavaniol group to have the fol- 

 lowing northward variations: A regular decrease in the thickness of 

 the group and in the relative proportion of sandstones ; a gradual 

 increase in the limestones, and a very little variation in the 

 coals. The most marked stratigraphic feature introduced in the 

 northern part of this group is the limestone beds. 



Bed 5 of the Muscogee-Cushing section is apparently the 

 Oologah limestone, since it has about the same stratigraphic posi- 

 tion and shows the decrease of limestone common to the southward 

 development of the beds. At and in the vicinity of Oologah this 

 limestone is massive, hard, gray, rather unevenly textured, and in 

 places contains gray chert nodules. On weathering, the limestone 

 breaks into irregular-shaped pieces. This bed forms an east-facing 

 escarpment fifty to one hundred feet high along the west side of 

 Verdigris river valley east of Oologah. The limestone bed next in 



1 This bed has been called the Oologah limestone because it is finely exposed 

 in Oologah, along Four Mile creek at the west edge of Oologah, and in an escarp- 

 ment some three miles to the east of that place. 



