ANCIENT WATER LEVELS OP CH A MPLAIN— HUDSON VALLEYS 137 



The precise boundaries of the retreating ice sheet are obscured 

 by the abundant deposits of sand and clay and by the further 

 blowing of the sands by winds in the district between Saratoga 

 and Gansevoort, so that in spite of several days spent in the 

 endeavor to trace the limits of retreating masses of ice I was 

 unable to get a satisfactory idea of the precise alinement of 

 the ice front across the valley in this field. 



Delta of the Batten kill [see pi. 11]. The Batten kill debouches 

 into the Hudson river at Schuylerville near the northern limit 

 of the main body of the Albany clays. A broad delta of gravels 

 and sands caps the clays on the east bank of the Hudson stretch- 

 ing back from the gorge to the low range of hills which forms 

 the eastern border of the Hudson valley. The Batten kill passes 

 westward through this range at Greenwich where the terraced 

 apex of the delta rises between 340 and 360 feet. Along the 

 western base of the hills the delta extends south of the stream as 

 a broad plain for nearly 2 miles. Three points leveled on the 

 inner upper margin of the deposit near the river are according 

 to the state map at elevations of 348, 344, and 358 feet respec- 

 tively, from which 350 feet may be taken as the approximate upper 

 level of the delta. Outward the delta falls off to the 320 foot 

 line with a very gentle slope and then descends more rapidly to 

 the 300 foot level. North of the stream at the base of Bald 

 mountain a considerable stretch of the delta plain lies between 

 300 and 316 feet above the present sea level. Since the outer 

 margin of the delta where it falls off most rapidly is a better 

 index of water level than the apical portion of the deposit 

 merging into the flood plain level which was probably built 

 above water level, it appears that the water level at this point 

 is approximately 320 feet above sea level. Southward of the 

 delta the clays and sands meet the base of the hills at about the 

 same hight. 



Northwest from Bald mountain and between the 300 foot level 

 and the river lies a lower plain whose surface is between the 

 220 and the 240 foot contour lines, a level which is well marked 

 at several places on either side of the Hudson gorge for 5 or 6 

 miles north and south of Schuylerville, but one which is very 

 close to that of broad areas of the bed rock in the immediate 



