164 NEW YORK STATE MUSEUM 
and sheeting it over with deposits of more or less assorted sand 
and gravel (fig. 1). Some of this buried ice persisted for a very 
long time, time being measured in terms of the establishment of 
unobstructed land drainage. Above about 2,coo feet the record 
is too obscure to decipher; most of the drift was left as sandy till 
and the deposits washed out over the surrounding ice fields were 
subsequently redistributed or destroyed by the disappearance of 
the underlying ice. At about the level of 2,000 feet, however, 
conditions locally permitted the building of waterlaid deposits 
on the land. Many of these have been preserved and, where not 
built out into open bodies of water, they show both by their external 
form and their internal structure that they were laid down along 
the margins of persistent ice masses, sometimes covering a thin 
margin and still retaining the slopes of contact, the kettle-hole 
record of buried blocks and the kames resulting from slump, Quite 
frequently the position of these highest plains is distant from any 
confining wall, in which cases they are either fragments of deposits 
originally more extensive or the filling of cavities in the ice. In 
the former case the deposit, flat-topped, is bounded by erosion slopes, 
in the latter by ice contacts or kames. 
At 1,800 feet the deposits of stratified drift laid on the ground 
(as indicated by the undisturbed stratification) become more 
numerous, and at about 1,600 feet begin to fall into a system of 
broad plains separated by wide spaces where the ice was not yet 
out. (See Loon Lake Quadrangle for good examples; north- 
western corner. ) 
The general northeast-southwest trend of the Adirondack main 
ridges served to deflect much of the southward drainage to the 
west. Partly because of this deflection and partly because the 
surface of the glacier remained higher in the Hudson and Cham- 
plain valleys, the high level sand plains and kame-belts are developed 
much more extensively along the western and southwestern margins 
of the mountains than at the southeastern base. 
Until the glacier had so far wasted away as to uncover the 
divide between the Black River basin and southern drainage, and 
to establish partly free lacustrine conditions in that basin, the 
succession of falling levels is exceptionally complete. For the 
most part these levels are marked by discontinuous sand-plains 
separated by areas of ice occupation in which the present streams 
follow consequent courses. The Post-Hochelagan uplift has 
warped the levels and much of the country is accessible with 
