GLACIAL AND POST-GLACIAL HISTORY 449 



(i) with valley trains leading down from positions marking the ice- 

 edge during its retreat: or (2) they head directly in kames or other 

 morainic developments which are just as significant in showing the 

 relation of the gravel plateaus to the source from which the material 

 was derived, and from which emanated the waters that transported 

 the delta materials to their present resting place. These kames and 

 moraines have been traced back from the immediate Hudson Valley in 

 a few cases, and have been seen to develop into fairly well-defined 

 morainic topography, while in the lower lands the morainic phenom- 

 ena are more subdued. Such kames and moraines are found at the 

 following places: (i) At the eastern and northeastern margin of the 

 South Schodack gravel plateau. The East Greenbush kame area 

 makes a part of this belt. (See Fig. 13, Nos. 73, 74.) (2) The 

 Teller hill kames (No. 75), which are fronted by clay without an 

 intervening gravel plateau. (3) The line of kames and moraine 

 extending from North Albany to Newtonville (No. 65.) (4) Kames 

 at Troy (No. 76). (5) Glen Lake-Hopkins Pond kame belt north of 

 Glens Falls (Fig. 18, Nos. 87 and 89. (6) Kames between New Scot- 

 land and Voorheesville (Fig. 13, Nos. 63 and 64.) (7) Kames at 

 Saratoga Springs (Fig. 13, No. 84.) (8) The Moreau Pond belt of 

 kames (No. 85.) That the relation of this kame belt to the gravel 

 pla eau east of it is similar to the relation of the kames and gravel 

 plateaus mentioned above, is not certain. 



The surface of the gravel plateaus is sometimes marked by ridges 

 or by deep sinks. The clay plain at the outer edge of some of these 

 plateaus has a higher level than at the same edge of the plain farther 

 north, or the reverse may be true. The clay plain sometimes fronts 

 kame areas without an intervening gravel plateau, and the top of the 

 kame area may be lower than the level of the gravel plateau immedi- 

 ately adjacent. On some of the streams, notably the Hoosick River, 

 deltas occur without the undulatory surface. From north of the lati- 

 tude of Mechanicsville to the northern part of Saratoga Springs, the 

 western part of the lowland is occupied by a succession of gravel 

 plateaus (area 50-75 square miles), with discordant levels which are 

 separated by depressions having a general northeast-southwest direc- 

 tion, and in the bottom of which are lakes such as Round Lake, 

 Saratoga Lake (with a length of 5-8 miles and a width of 2 miles). 



