PHYSICAL AND CLIMATIC SETTING 7 



to one hundred feet above its surface. This is a clay 

 plain with the exposed edge eroded into a system of 

 steep slopes. It narrows and widens according to 

 the position of the adjacent rock-cored hills. The 

 plain is best developed above Troy and from there to 

 a little above the great westerly bend of the Hudson 

 River, in Washington and Saratoga counties, it is a 

 broad plain, mostly capped by sand and gravel. 

 From point to point the valley widens to receive some 

 inflowing tributary, the largest of which on the west 

 is the Mohawk Eiver opposite Albany and Troy. 

 On the east the most important tributary is the Hoo- 

 sic Eiver in northern Eensselaer County. 



North of the "Great Bend" at Hudson Falls 

 the general valley region is constricted to a very nar- 

 row pass by the east flank of the Adirondacks to unite 

 with the Champlain Valley. For a number of miles 

 there is only this narrow rock-walled lake, but further 

 north near Ticonderoga the hills recede a little and 

 place is given to a low and rather narrow lake-plain 

 terrace of clay, with here and there sand and gravel 

 shelves. The surface is undulating. The plain wid- 

 ens toward the north, though at places it is con- 

 stricted. The greater width of lowland is on the 

 Vermont side. In Clinton County the plains region 

 blends with low hills that successively rise to the 

 Adirondack Mountain system. 



The Mohawk Valley which breaks out from the 

 Hudson region at Troy is a V-shaped trough lying 

 between the Adirondack and the Catskill mountains. 

 Both masses approach the river by a succession of 



