ANCIENT WATER LEVELS OP CHAMPLAIN-HUDSON VALLEYS 191 



Before passing to the notice of the outlet of Lake Vermont, it is 

 desirable to determine, if possible, from the facts in hand the 

 nature of the change which brought about a separation of the 

 clay-depositing waters which extended from the upper Hudson 

 valley into that of Champlain. On plate 28 of this report, a line 

 (A-B) is drawn on the profile for the purpose of comparing cer- 

 tain water levels which occur at indicated points on the sides of 

 the Hudson and Champlain valleys. The plane in which this 

 line lies has a tilt from north to south at the rate of about 2 feet 

 to the mile. The line is drawn through two of the highCiSt beaches 

 found between Port Kent and Saw^'ers hill at Street Road on the 

 New York side of Lake Champlain. It is possible that these 

 beaches are not contemporaneous. From Street Road to New 

 York city there are practically no kettle holes now remaining 

 unfilled in the drift below the levels which this inclined plane 

 traces on the sides of the valley, except it be that the large kettle 

 holes in and about Glen lake descend below the plane, with their 

 tops, however, well above it. The kettle holes quite uniformly 

 fall off in level to the south in rude parallelism with this plane 

 of comparison. 



From the southern border of the Highlands of the Hudson 

 southward the sand plains and terraces contemporaneous with 

 ■ the retreating ice front rise to the northward in succession in 

 close parallelism with this plain and approximately to equivalent 

 elevations. Throughout the middle Hudson valley there is less 

 accord in elevation of the actual deltas and this projected 

 plane of comparison. It has proved well nigh impossible to 

 find any systematic relation of the various water levels which 



I are indicated in this portion of the valley, after making due 

 allowance for such deposits as appear from their form or struc- 

 ture to have been built in waters confined along the ice margin 

 or held up on the rock terraces of the Hudson gorge by ice remain- 

 ing in it. In general there is clearly indicated, however, a rise 

 of the water levels toward the north at something like the same 

 rate of tilting as that indicated by the line of comparison; but 

 ■the upper limit of the deposits falls below that of the plane of 

 comparison as if at this later stage of delta building along the 

 ice border in the river either the land had risen or, if it were 



