the Middle Atlantic Slope. 455 



by H. D. Rogers and Cook, to overspread peninsular New 

 Jersey ; (5) that the identity of the New Jersey gravels with 

 the stratified deposits of Gardiner's Island, Long Island, San- 

 coty Head and Shirley Point has been satisfactorily shown 

 upon paleontologic grounds by Desor, Sanderson Smith, Yerrill, 

 Merrill and Britton ; and (6) that the series of deposits has 

 been shown by Cook, Merrill, Britton and others, to pass be- 

 neath the terminal moraine and its derivatives. In short, col- 

 ligation of all recorded observations indicates that the entire 

 Coastal plain of the Middle Atlantic slope is occupied by a 

 series of stratified deposits, abounding in bowlders and coarse 

 gravel along the fall-line and bearing recent marine fossils 

 toward the coast, which are overlain unconformably by the 

 terminal moraine in the north. 



He viewing the inferences of the same students as to the 

 genesis and age of the formation it appears (1) that all consider 

 it subaqueous ; (2) that the Rogers brothers. Booth, Conrad, 

 Mather, Lyell, Tuomey, Desor, Tyson, Sanderson Smith, Yer- 

 rill, Cook, Kerr, Chester, Merrill, Britton, and perhaps others 

 hold it to be marine ; (3) that W. B. Rogers, Sanderson Smith, 

 Cook, Cope, Kerr, Fontaine, Lewis, Chester, and others be- 

 lieve it was deposited during a period of low temperature; (4) 

 that all refer it, wholly or in part, to the later Tertiary or 

 Quaternary ; and (5) that Cook, Merrill and Britton regard it 

 as pre- glacial. 



The several observations and inferences are in accord with 

 those recorded above, and are here generalized only to corrob- 

 orate conclusions reached independently after personal study 

 (chiefly along the inland margin of the formation) in North 

 Carolina, Yirginia, the District of Columbia, Maryland, Dela- 

 ware, Pennsylvania, New Jersey and New York. 



Taxonomy. — The local relations. — By stratigraphic position 

 and paleontology the Columbia formation is proved to be 

 newer than any of the recognized Tertiaries of the Middle 

 Atlantic slope, and its fauna is of modern facies. It therefore 

 appears to be Quaternary or Pleistocene in age. 



By (1) stratigraphic relations, (2) amount of erosion, and (3) 

 degree of alteration, the formation is proved to be much older 

 than the terminal moraine or the drift sheet whose margin it 

 marks : 



1. In the valleys of the Susquehanna and Delaware the ter- 

 minal moraine is superimposed upon Columbia terraces and in 

 part composed of Columbia materials ; and similar relations 

 have been repeatedly observed in New Jersey by Cook, on 

 Staten Island by Britton, and on Long Island by Merrill. 



2. A rough quantitative measure of the relative antiquity of 

 the two deposits is found in the erosion they have suffered. 



