Recent or Rise of the land to its Continued subsidence of Terrace. present height, or coast at New York and (Mostly within somewhat higher, soon southward, and rise of the period of after the departure of the mountainous belt, by traditional the ice. Rivers eroding displacement along the and written their glacial fall line of the rivers. history.) flood-plains, leaving Much erosion of the remnants as terraces. Columbia formation since Warmer climate than now, culmination of second probably due to greater Glacial epoch; Gulf Stream, formerly sedimentation in bays, permitted southern sounds, and estuaries. mollusks to extend to Gulf of St. Lawrence, now represented by isolated colonies. Glacial Period of Ice Age. Pleistocene Period. Champlain. Land depressed under Less subsidence in ice-weight; glacial latitude of New York and (Close of the recession; continued southward than at north; second Glacial deposition of upper till lower Hudson Valley, and epoch.) and deep flood-plains of part of its present gravel, sand and clay submarine continuation, (modified drift). above sea-level. Gravel Terminal moraines marking and sand deposits from pauses or readvance englacial drift in during general retreat of Delaware and Susquehanna ice. Marine submergence. Valleys, inclosing 150 to 230 feet on coast abundant human implements of Maine, to 520 feet in at Trenton, N.J. Gulf and valley of St. Lawrence. Second Glacial. Second great uplift of Renewal of great the land, 3.000 to 4,000 continental elevation feet higher than now; (3.000 feet in latitude snow-fall again all the of New York and year; ice probably two Philadelphia), of miles thick on Laurentide excessive snow-fall and highlands, and extending rains, and of wide-spread somewhat farther south fluvial deposits, the here than in first Columbia formation, on glaciation. Lower till the coastal plain, during (ground moraine), and early part of this epoch. upper till (englacial Implements of man at drift). Terminal Claymont, Del. moraines, kames, osars, valley drift.