32 



of the State, notably on Goose Creek and on the Ashley. The geo- 

 graphical situation of these remnants of beds indicates that the 

 Miocene formation was deposited continuously over the lower part 

 of the Coastal Plain area of the State, but has been so extensively 

 eroded as to leave only these fragments here and there. 



The Pliocene in South Carolina may be looked upon as divided into 

 a fossiliferous and a non-fossiliferous member. The latter is called 

 Lafayette, but may prove to be of the same age as the fossiliferous 

 Pliocene. The fossiliferous beds are well cut into by the Waccamaw 

 River, and afford many species of fossils, and are seen to contain an 

 occasional nodule of phosphatic material. The presence here of phos- 

 phate in well-determined Pliocene deposits, together with the fact 

 that the Pliocene beds of Florida are highly phosphorated, lead us 

 also to consider the phosphate beds in the region about Charleston 

 to be either Pliocene in age or else to have been phosphorated during 

 this period. These facts, combined with the occurrence of Pliocene 

 fossils from a depth of sixty-five feet in the artesian wells of Charles- 

 ton, indicate that the fossiliferous Pliocene may underlie the surface 

 formation of a large part of the coast of the State. The color of the 

 sand and clay in which the fossils on the Waccamaw are embedded, 

 is yellow and in marked contrast to the gray sands above. This fur- 

 nishes a connecting link between the fossiliferous Pliocene and the 

 Lafayette farther inland, which is everywhere seen to consist of 

 "orange-colored" sands and clays. Future detailed work may reveal 

 an intergrading of the two members. It at any rate seems perfectly 

 safe, from its occurrence elsewhere, to regard the Lafayette as Plio- 

 cene. According to McGee 1 , the Lafayette formation extends across 

 the State in a broad belt at an elevation varying from 25 to 650 feet 

 above tide level. In the western part of its extent the Lafayette rests 

 unconformably upon the Piedmont crystallines in some instances, 

 and again upon the Potomac. Toward the east it rests unconforma- 

 bly upon the Miocene, Eocene or Marine Cretaceous. It varies in 

 thickness from thirty to eighty feet. Though "orange colored" for 

 the most part, yet there are marked variations in the color of the 

 sands, clays and loams which compose the formation. Sometimes 

 the color is a chocolate brown, at other times a brighter red than the 

 usual orange. The Pliocene is everywhere, except, perhaps, on its 

 western margin, unconformably overlaid by the Pleistocene; or, 

 differently expressed, the Lafayette is everywhere unconformably 



1 "Three Formations of the Middle Atlantic Slope" (Am. Jour. Sci., 3d 

 ser., Vol. XL, 1890). 



