SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 'J'J 



oil reservoirs and drilling is being actively pursued on such areas 



(fig- 25). 



From a paleontological standpoint, the Mississippian formations 

 following the black shale were of highest interest. Usually in Ten- 

 nessee the rather unfossiliferous Fort Payne chert of Keokuk age 

 succeeds the Chattanooga black shale but in parts of the Lillydale 

 quadrangle two intervening formations were discovered. These were : 

 first, the Ridgetop shale of Kinderhook age reaching a thickness of 

 200 feet, and second, the richly fossiliferous New Providence shale 



Fig. 26. — Batocrinus spr'mgeraniis Bassler, a new species from the Lower 

 Keokuk, Overton County, Tennessee; slightly less than natural size. (Pho- 

 tograph by Bassler.) 



of Burlington age noted particularly for its crinoid fossils. Detailed 

 mapping showed that these two formations were not deposited over a 

 wide area but that they occupied ancient embayments of the sea 

 surrounding the Cincinnati anticline. The succeeding strata in the 

 quadrangle are of Keokuk, Warsaw. St. Louis and Chester age and 

 show a more uniform, widespread development. The Keokuk lime- 

 stone, however, exhibited different characteristics from its usual devel- 

 opment in Tennessee as the Fort Payne chert, but the relationships 

 between these strata will have to be determined from future studies 

 ot a more extended area. Paleontologically this formation in the 



