T. C. Brown — Fauna from Chappaquiddick Island. 237 



and Virginia, and Dall, in his correlation tables of the JSTorth 

 American Tertiaries, has placed them in the Claibornian stage 

 or equivalent to npper Middle Eocene. The fossils of this 

 province differ so widely from those of the regions immedi- 

 ately to the south that correlation is very difficult, and even 

 now there is doubt as to the exact position of these beds. 



A second province of the Eocene, generally known as the 

 Pamunkey formation from its typical development along the 

 Pamunkey Piver in Virginia, begins in Delaware and extends 

 across Maryland well into Virginia. Lithologically these 

 deposits have more similarities to those of the provinces to the 

 south than to the Shark Piver beds of New Jersey, yet they 

 are sufficiently distinct both lithologically and in their con- 

 tained fauna to require complete separation. According to 

 Clark these deposits " constitute a single geological unit." 



A third province embraces the Eocene deposits of the Caro- 

 linas and Georgia and affords a far more complete series of 

 Eocene strata than either of the more northern areas. The 

 lower beds consist of arenaceous and conglomeratic deposits, 

 rather sparingly fossiliferous, probably because the material by 

 its very nature was not adapted to permit the preservation of 

 fossils. The middle and upper beds are well developed and 

 represented by limestones and marls containing an extensive 

 fauna, yet quite distinct from the surrounding provinces. 



A fourth, the Gulf province, is by far the most extensive of 

 the Eocene areas. It extends from Florida to Texas and 

 includes the so-called Mississippian embayment, an area extend- 

 ing well up into the Mississippi basin. All stages of the 

 Eocene are more fully represented, but both lithologically and 

 paleontologically this province is very distinct from those 

 along the Atlantic coast. Peculiar conditions in this area 

 resulted in the interbedding among the other deposits of many 

 lignitic strata. 



A fifth marine Eocene province occurs along the Pacific 

 coast, and outcrops along the coastal range in California, Ore- 

 gon and Washington. These deposits are generally known as 

 the Tejon group and were originally referred to the Cretacic. 

 Later study has shown them to be of Eocene age, and yet their 

 fauna differs widely from those of the Atlantic and Gulf 

 provinces. 



The fauna from Chappaquiddick represents a new and dis- 

 tinct Eocene province, differing from all the other provinces 

 but no more widely different from these than they are from 

 one another. Although in this fauna there are several species 

 somewhat resembling those of the provinces to the south, on 

 the whole it would seem to be more closely allied to the 

 Eocene of England. The genera most abundantly represented 



