21 



overlaps upon the crystalline area of the Piedmont Plateau, espe- 

 cially along stream channels cut in these rocks. It is divisible 

 throughout this stretch of country into two general divisions : ( I ) 

 That just along the present shore line, extending back a few miles 

 only, composed of sands, clays and loams fairly well stratified and 

 containing fossils, in most cases overlaid by recent sands and coarser 

 material. (2) That extending from the old Pleistocene shore line and 

 in some cases, from up the stream channels some distance down to 

 within a few miles of the present shore line, to where it intergrades 

 into the fossiliferous Pleistocene. The beds of this second division, 

 consisting of sand, gravel and (in the northern part) bowlders, mixed 

 with finer sands, clays and loams, are not so well stratified as are the 

 beds of the other division, and contain no marine invertebrate fossils. 

 It is of much greater area than the first division, and is the surface 

 formation throughout much of the Coastal Plain region. In the north- 

 ern half of this stretch of country, the non-fossiliferous portion of the 

 Pleistocene or the Columbia seems to be capable of a ready division 

 into two or more formations. This is especially true in New Jersey and 

 Maryland, where it has been studied more thoroughly than else- 

 where. Also in Virginia divisions have been made. In the southern 

 part, especially in South Carolina, no suitable basis for subdivisions 

 has as yet been found. 



Outside of this broad continual mantle of Pleistocene or Columbia 

 sands, there are disconnected areas of it to the north) of New Jersey, 

 along the coast of New York and New England and on the neighbor- 

 ing islands, and indeed on up to Labrador and Greenland. It is well 

 to note here that the Pleistocene is generally considered to have been 

 ushered in with the first great advance of the ice-sheet from the 

 North into more southernly latitudes — with the Glacial Epoch, in a 

 word. Therefore, in this northern part of the formation, the deposits 

 consist largely of the product of glacial action ; clay, sand and bowl- 

 ders, arranged in the way peculiar to glacial action or to the influence 

 of glacial action. Of course, where the deposits have been subma- 

 rine, the material may have been reworked and changed from strictly 

 glacial deposits. The Pleistocene deposits about Lake Champlain 

 and along the St. Lawrence and elsewhere along the coast north of 

 Maine may, in this discussion, be set aside and the tracing begin with 

 Maine and extend only to Florida. This includes the Pleistocene that 

 is closely related to this formation in South Carolina. It seems best 

 to treat the Pleistocene by States. 



