PLEISTOCENE MARINE SUBMERGENCE 1 5 



In 1 89 1 and 1892 Heinrich Ries published descriptions of the 

 massive clays of the Hudson valley (33, 34), from Croton Point to 

 Albany, and in later publications (35, 36) gave detailed description 

 which proved their estuarine origin. 



N. H. Darton, in 1894, published descriptions of the Pleistocene 

 deposits of the counties of Albany (38) and Ulster (39). He also 

 regarded the deposits as the "products of a submergence at the 

 close of the Glacial epoch," and drew a map of the " Champlain 

 submergence" of the Albany district (38, page 359). 



An admirable description of the delta of the Catskill in the Hud- 

 son estuary was published by W. M. Davis in 1892 (37). He 

 •clearly recognized that the Champlain submergence involved the 

 Hudson valley. PTis value for the summit of the Catskill delta, 

 about 275 feet, is precisely correct, as shown by the profile, plate 10. 



In his Glacial Geology of New Jersey, R. D. Salisbury describes 

 the features due to Postglacial submergence, and says that the 

 water plane has about 100 feet altitude at the north border of the 

 state. This is in accordance with the plotted profile. 



Some later writers on Long Island stratigraphy and glacial beds 

 have assumed or asserted an uplifted attitude of the lower Hudson 

 district, but have passed over the earlier writings and entirely 

 ignored the clear and positive evidence oi submergence. 



For the Connecticut valley the detailed studies of B. K.' Emerson 

 show conclusively that the high sand plains and the extensive clay 

 fields were the products of standing water, which he called " Con- 

 necticut lakes," and could not be the results of a swollen river 

 (66, 67). His altitudes for the water plane on the north and south 

 lines, of Massachusetts are values used in the map of isobases, 

 plate 9. 



Students of the Champlain section of the great valley have made 

 too much distinction between the lower deposits which carry salt- 

 water fossils and tlie upper plains and terraces without fossils. 

 There is probably also a psychologic factor involved. The invoking 

 of " glacial waters " may have been due in part to a tendency to 

 utilize the new thought in Pleistocene geology, the existence and 

 effect of ice-dammed waters. The recognition of glacial lakes 

 came during the seventies of the past century,^ and has been a 

 most useful conception. But it was always incumbent on an author 

 who postulated glacial waters to find the control, or locate the out- 

 let and correlate the levels and beaches with their outlets. There 



^ Proc. Amer. Assn. Adv. Sci., 47: 285-2S7; Amer. Geo!., 22: 183-S6. 1898. 



