448 CHARLES EMERSON PEET 



is that of a plain descending gradually from the valley sides to the 

 bluffs (of clay generally) bordering the present Hudson. The eleva- 

 tion, on the whole, increases from the south, where it is loo or 120 

 feet to 180 feet, toward the north, where it is 220-240 feet along 

 the bluffs of the present Hudson. From these elevations marking 

 the bottom of the trough or the meeting of the slopes of the sea- or 

 lake-floor, the plain rises eastward and westward to the higher land 

 marking its limits. (See Fig. 14.) 



Gravel plateaus and deltas. — Above the plain on the east and 

 on the west rise gravel plateaus, some of them delta-like in form, 

 which represent approximately the level of the watei-s when the floor 

 above described was being built up. These gravel plateaus and 

 deltas are found at the following places: On the left bank — (i) South 

 Schodack and northwest at 340-360 feet; (2) Troy, 300 and 360 

 feet ( ?) ; (3) Hoosick River, 360 and 280-300* ' ( ? ) feet; (4) Batten 

 Kill, 380-400 (?) and 300 feet; (5) At Glens Falls and vicinity, 460 

 (?), 389, 340*, and 280-300* feet. On the right bank — (i) South 

 Bethlehem, at 300, 240*, and 200-220* feet; (2) at Maltaville, 

 340-360 feet; (3) at Saratoga and vicinity, 400 ( ?), 320-340, 300, and 

 260 feet ; (4) southwest of Glens Falls, 340* and 380 feet- — a continu- 

 ation of the Glens Falls levels of the left bank. 



The plateaus descend abruptly toward the plain. The layers of 

 coarse gravel and sand of which they are generally made may some- 

 times be seen to dip at high angles in the same direction and to grade 

 down the dip into the fine materials, and into the clay which makes 

 up a large part of the plain. They are like those of Class 2 of the 

 lower Hudson. The height of the gravel plateaus above the level 

 of the floor varies from 160 to 180 feet on the north to 100-120 or 140 

 feet in the southern part of this area. While these gravel plateaus 

 descend abruptly toward the old lake- or old sea-floor, and the 

 stratification bears the significant relation to the clay plain mentioned 

 above, the relation of the gravel plateaus up the slope of their surface 

 is just as significant. When traced back they are found to connect, 



I The stars indicate secondary deltas. Perhaps the 300-foot Troy deha should 

 be considered secondary. Perhaps a part of the 300-foot delta on the Batten Kill is 

 not secondary. It has been seen only in its northern part. Its southern part as rep- 

 resented on Fig. 13, No. 91 is hypothetical. 



