24 EOCENE AND LOWER OLIGOGENE CORAL FAUNAS. 



Genera represented in the Eocene of the United States and depths at which ihcy non- 

 live — Continued. 



Fathiims. 



Balanophyllia Shallow water to 400 



Eupsammia. 



Rbectopsammia gen. nov. 

 Endopachys. ' 



Dendrophyllia Shallow water to 750 



Dendracis, extinct. 



Tnrbinaria Shallow water. 



Porites Shallow water. 



Total number of genera 36 



Recent as well as fossil genera 24 



Extinct genera, including the seven new genera 11 



Probably extinct 1 



Analysis of the recent genera. 



Exclusively shallow water 9 



Shallow water to 50 fathoms 1 



Shallow water to 150 fathoms 1 



Shallow water to 315 fathoms 1 



Shallow water to 400 fathoms 1 



Shallow water to 750 fathoms 2 



Shallow water to 1,500 fathoms 2 



From 38 to 300 fathoms 1 



From 50 to 300 fathoms 1 



From 100 to 220 fathoms 1 



From 100 to 750 fathoms 1 



From 158 to 892 fathoms 1 



Data deficient concerning 2 



Total 24 



Of the twenty-two g-enera concerning' whicli we have definite informa- 

 tion, eighteen occur in water less than 50 fathoms deep, and ten occur only in 

 water less than .50 fathoms deeji; all may occur in water 100 fathoms 

 or less in depth, Amphihelia doubtfully excepted. The fauna as a whole 

 is one of only moderately deep or shallow water. 



We shall now discuss the probable conditions of depth under which the 

 various beds of the Eocene in tlie diffei'ent States were deposited, so far as 

 the corals enlighten us. 



' In Gnlf of California 39 fathoms (coll. U. S. Nat. Mus.). 



