64 NEW YORK STATE MUSEUM 
Briefly summarized: No deposition of Jurassic strata occurred 
within the borders of New York State but instead, the region was 
well above water and undergoing active erosion so that by the close 
of the period this region, as well as the whole Atlantic slope, had 
been worn down to the condition of a fairly good peneplain. 
CRELACIC TSO Rs 
The Cretacic period opened with the eastern coast line of the 
eastern United States somewhat farther out than it now is, but 
early in that period there was enough subsidence, or possibly warp- 
(Ke eee 
VE Ey IT DS - 
ab) ee aE 
7a BSS 
——— 
TG 1d 7A\ aaa 
CS5 SE eae 
= 
Fic. 21 Generalized map of North America in the Upper Cretacic period, 
showing the relations of land and water. Horizontal lined areas = land; 
blank areas — water. The sea then spread over the Atlantic coastal plain 
region including Long and Staten Islands of New York. During the next 
(Teritary) period, the conditions were much the same along the Atlantic 
and Gulf coasts, but in the west the great interior sea had disappeared. 
