98 Upper Cretaceous Fauna from Tennessee [296 



shells with coarse, vigorous ornamentation, yet many pos- 

 sessed small, delicate, fragile and. thin shells, but have never- 

 theless been preserved perfectly to the present. Individuals 

 of species of Leda, Cadulus and Teinostoma are smaller than 

 a wheat gain. Yoldia, Anatimya, Tenea, Liopistha, Leio- 

 straca are represented by delicate and fragile individuals. 

 One species of Crenella is thinner than paper yet it is ele- 

 gantly sculptured. 



It is impossible to postulate with assurance the depth of 

 the water in which the Coon Creek fauna lived. Such fami- 

 lies as the Pernidae, Volutidae and Lytoceratidae, which are 

 very prominent in the assemblage, are usually regarded as 

 dwellers in the open sea at a depth of about 50 fathoms. 

 Yet the Nuculas, Corbulas, and Naticoids, etc., are for the 

 most part dwellers in shallow water near shore. Lobsters 

 and true crabs lived in great abundance in the Eipley sea as 

 is shown by the remains of these forms which are very com- 

 mon in the Coon Creek sediments. There are probably five 

 genera of the Eucrustacea, among which is a large crab about 

 seven inches across from .right to left and whose modern 

 affinities live in the intertidal zone of the seas. No fora- 

 miniefra have been found. Only two very small individuals 

 of two species of corals have been recovered. These last two 

 facts, together with the very abundant crab remains indicate 

 very near-shore or intertidal waters as the habitat of the 

 Coon Creek fauna. 



As regards the evidence furnished by the sediments there 

 is no well-marked cross-bedding which would result from 

 strong current action. However, the very presence of clastic 

 material such as sand and clay require currents to account 

 for transportation, and shifting of these currents to explain 

 the intermingling of these materials. The great abundance 

 of pelecypods which are organisms that feed for the most 

 part on plankton is indicative of waters disturbed by cur- 

 rents, instead of very calm seas, for plankton occurs mostly 

 in water that is agitated by currents. No pebbles whatever 

 have been observed in the sediments of the Coon Creek 



