146 THE INTERPRETATION OF THE PALEONTOLOGICAL CRITERIA 



(Byrgiscus) interrupta (Totten), Crepidula fornicata (Linne) Polynices 

 (Neverita) duplicaius (Say), Barnea (Scobina) costata (Linne), Cor- 

 bula contracta (Say), Mya arenaria Linne, Mulinia lateralis (Say), 

 Bangia cuneata (Gray), Ensis directus (Conrad), Cumingia tellinoides 

 (Conrad), Macoma balthica (Linne), Tagelus gibbus (Spengler), Betri- 

 cola pholadiformis Lamarck, Venus mercenaria Linne, Ostrea virginica 

 Gmelin, Area (Noetia) ponderosa Say, Area (Scapharca) transversa Say, 

 Nucula proxima Say, Leda acuta (Conrad), Yoldia limatula (Say). 



There are other localities in South Carolina and Georgia at which ma- 

 rine Pleistocene fossils have been recognized, although the list is by no 

 means as extensive as that of Simmons Bluff. 



Dr. Dall has described the Pleistocene marine deposits of North Creek 

 near Osprey on Little Sarasota Bay, Manatee county, on the west coast of 

 Florida which contain the following Maryland Pleistocene forms : 

 Tornatina canaliculata (Say), Terebra dislocata (Say) Oolumbella (As- 

 tyris) lunata (Say), Odostomia acutidens Dall, Crepidula plana Say, 

 Bolynices (Neverita) duplicatus (Say), Mulinia lateralis (Say), Ma- 

 coma baltliica (Linne), Ostrea virginica Gmelin, Area (Scapharca) 

 transversa Say. 



An examination of the lists of forms which have been given for the 

 various Pleistocene localities from Massachusetts to Florida shows the 

 large number of identical species from each, and the strong probability 

 that they are essentially contemporaneous. 



GEOLOGICAL RANGE OF SPECIES. 



The Pleistocene species of Maryland date back in some instances into 

 the early Tertiary, although the great majority of forms made their first 

 appearance in the late Miocene or Pliocene. The following table shows 

 the range of the individual species from which it will be noted that one 

 appears in the Eocene, five in the Oligocene, fifteen in the Miocene, thi rty 

 in the Pliocene. Of the remainder twelve are not known earlier than the 

 Pleistocene. All are living to-day. 



Nearly all of the marine forms are found living at the present time off 

 the coast of Maryland and Virginia. A striking exception is to be found 



