1897. ( DRAKE — THE GEOLOGY OF INDIAN TERRITORY. 875 



The strata between the McAlester and Mayberry coal beds ap- 

 parently are more diversified. In the Cavaniol mountains four 

 thick sandstone beds alternating with clay shales intervene between 

 the coals. Northwest of San Bois there are three intervening sand- 

 stones, while to the west of Sans Bois two sandstone beds inter- 

 vene, and east of Brooken only one of prominence lies between the 

 two coal seams. This shows a decrease in the number and thickness 

 of intervening beds to the northwest. The intervening sandstone 

 beds, especially those in Cavaniol and Sans Bois mountains, are 

 usually from fifty to two hundred feet thick and are evenly textured 

 strata that usually have smooth bedding planes, and vary 

 from flaggy to massive sandstone. The first sandstone below the 

 Mayberry coal is especially flaggy and smooth where it was seen 

 on the east end and north side of Cavaniol mountain. The dark 

 gray clay shales interstratified with these sandstones are from two 

 hundred to five hundred feet thick. South of the Arkansas river 

 a coal seam four to eight inches thick occurs almost regularly one 

 hundred feet above the McAlester coal. 



A rough estimate of the thickness and stratigraphy of the Cava- 

 niol group north of the Canadian river, along a line running from 

 McDermitt through Checotah and Starvilla to the mouth of the 

 Canadian river, is as follows : 



FEET. INCHES. 



Coal , 2 6 



Gray, arenaceous clay shale 50 



Friable, shaly and massive sandstone and 



• some clay shale 300 



Gray, arenaceous clay shale 500 



Sandstone 10 



Clay shale 25 



Coal 10 



Clay shale 200 



Sandstone 25 



Clay shale 100 



Coal 8 



Clay shale 50 



Coal I 3 



Clay shale 50 



Sandstone and some interstratified clay 



shale 100 



Clay shale 300 



Coal I 6 



Total thickness (approximate).. 1700 



