Topographical features of the Kew Haven region. 67 



to the south it diminished in height, being but 30 feet in tlie latitude 

 of Halleck's place on the bay. The facts on this point are given be- 

 yond (p. 88). North of Connecticut, over New England, the amount 

 of depression below the present level was still greater, and increas- 

 ingly so with increase of latitude, it having beeri 200 to 250 feet at 

 least in central New Hampshire, 400 about Lake Champlain, and 500 

 feet on the St. Lawrence. 



2. General consequences of the Subsidence. — As the writer has re- 

 marked upon elsewhere, an immediate consequence of a subsidence of 

 the land, and especially of one which was greatest as a general thing 

 to the north, would have been the bringing on of a warmer climate, 

 and thence, the commencement of melting in the glacier. 



As another result we note that the slope of the great valley of the 

 Connecticut would have become less than it is now. Consequently 

 the motion of the Connecticut valley glacier would have been greatly 

 retarded, if not rendered altogether null. Moreover the rivers would 

 have had a diminished rate of flow, and would therefore have spread 

 in wider floods than ever before, becoming in some parts a series of 

 lakes ; and the lakes also Avould have had an unwonted expansion. 

 The great flow of waters from the melting ice would have immensely 

 augmented the floods in all directions. 



Such an extended change of climate over the glacier area was 

 equivalent in effect to a transfer of the great glacier from a cold icy 

 region to that of a temperate climate and melting sun. The melting 

 would therefore have gone forward over vast surfaces at once, wide in 

 latitude as well as longitude, and not merely along a southern edge 

 with slow creeping progress northward. Hence, as another result, 

 the depositions of sand, gravel and stones from the glacier, would 

 have taken place almost simultaneously over regions scores of miles 

 wide in latitude, and in general without special accumulations along 

 a southern border like what is called the terminal moraines in the 

 Alps. They would have descended alike over the hills, plains, and 

 valleys, lake regions, flooded rivers and sea-shoi-e bays ; but not with 

 like results over these various regions, for wherever there was water 

 in motion beneath, the water would have worked over the pebbles 

 and sand and produced some stratification of the material, or at least 

 have leveled all off at top. Thus unstratified and stratified drift (the 

 latter including the so-called modified drift, as well as a large part of 

 the "alluvium" of river valleys) were formed simultaneously, and 

 both in the Champlain era. 



The depositions made directly from the glacier as a consequence 



