MARYLAND GEOLOGICAL SURVEY 141 



CORRELATION WITH MORE DISTANT AREAS. 



The marine fauna of the Maryland Pleistocene is found largely repre- 

 sented at a number of localities along the Atlantic border from Massa- 

 chusetts to South Carolina, while identical forms likewise appear in the 

 Florida and Gulf coast Pleistocene., which must of necessity from its more 

 southern latitude show increasingly greater differences. The same change 

 is apparent in going northward. The purely southern forms gradually 

 disappear and are replaced by those of boreal and arctic habitat. As the 

 colder-water deposits of the glaciated region are reached the southern 

 forms finally disappear altogether, and the fauna of this northern Pleis- 

 tocene presents an entirely distinct facies. 



The Maryland Pleistocene from its central location naturally shows 

 an intermingling of southern and northern species. Most of the forms 

 found in Maryland also range as far south as South Carolina, although 

 the latter area has many species of southern habitat not known in Mary- 

 land. 



Most, if not all, of the localities in the Atlantic coast province, which 

 have afforded these closely similar marine faunas, are from their geologi- 

 cal and geographical position evidently of middle or late Pleistocene age. 

 Many of them have been personally visited by the author and his asso- 

 ciates and the relations of the deposits examined. In most instances, 

 from New Jersey southward, the equivalency of the beds to the Talbot 

 formation of Maryland has been clearly established. 



The map, Plate II, shows the distribution of the Pleistocene de- 

 posits along the Atlantic and Gulf borders. No attempt has been made 

 to divide them into their several formations since too few facts are at 

 present available for this purpose. The examinations made at various 

 points along the coastal border show the wide distribution of physical 

 and faunal conditions similar to those existing in Maryland. It is, there- 

 fore, highly probable that the Maryland formations will be found through- 

 out most if not all of the marine Pleistocene belt. 



The most northern marine Pleistocene locality which has afforded any 

 considerable number of species in common with the Maryland area, is 

 that at Point Shirley near Boston, the forms being largely those found 



