19G C. R. KEYES — A DEPOSITIONAL MEASURE OF UNCONFORMITY 



(4) The present Ozark uplift had no effect in determining the depo- 

 sition of the Coal Measures. 



(5) The Poteau group of Arkansas, the Cavaniol of Indian territory 

 (containing the Grady and McAlester coals) are practicall}^ coextensive 

 with the Des Moines series farther north (Lower Coal Measures). 



(6) The Poteau group of Indian territory (Drake) corresponds about 

 to that part of the Missourian below the Plattsniouth limestone, and 

 entirely overlies the Poteau of Arkansas. 



