904 GEOLOGY 



deposition, in another way, for the reduction of temperature 

 probably attended by a reduction of vegetation, and an incn 

 of erosion. The reduction of vegetation was probably greatest 

 just where erosion was most readily stimulated, namely, in the 

 higher altitudes. 



It is conceived, therefore, that the deposition of the principal 

 subdivisions of the Quaternary series of the Coastal Plain resulted 

 from the combined effect of slight surface warpings and climatic 

 changes; that epochs of notable deposition alternated with epochs 

 when erosion was dominant in the same regions; and that the ma- 

 terials of each principal stage of deposition were deposited, shifted, 

 and re-deposited repeatedly, so that the Bridgeton, the Pensauken, 

 and the Cape May formations are each really complex series, though 

 they nowhere attain great thickness. 



While the Cape May division of the Quaternary was being 

 deposited, the sea transgressed some parts of the present coast to 

 a slight extent, at the same time that deposition was taking place 

 in the valleys scores of miles inland, and in some cases hundreds of 

 feet above sea-level. If similar relations existed during the earlier 

 stages of Quaternary deposition, the seaward edges of the deposits 

 of each principal stage of deposition may be marine. It is probable 

 also that the series contains estuarine phases of sedimentation, and 

 it can hardly be doubted that each subdivision now recognized on 

 the land has its synchronous marine phase beneath the sea. 



The Cape May formation was essentially contemporaneous with 

 the last glacial epoch, and it seems not improbable that the earlier 

 members of the Quaternary system of the coast were made durum 

 earlier glacial epochs. 



In recent times, dunes have been developed at numerous points 

 along the coast, and their development and destruction is still in 

 progress. 1 Humus deposits also have somewhat extensive develop- 

 ment in the tidal marshes, and to a less extent elsewhere. 



In the Interior 



Some of the non-glacial Pleistocene formations of the interior, 

 notably the loess, the valley trains, etc., have been referred t>. 

 1 See for example, the Norfolk, Va.-N.C., folio, U. S. Geol. Surv. 



