GEOLOGY OF SARATOGA SPRINGS AND VICINITY I47 



and, at its greatest extent, perhaps as far north as Whitehall. 

 Fine clays were deposited in its waters and huge sand deltas were 

 built along its shores by the streams which flowed into it. The 

 great terraces of clay and sand which occur both east and west 

 of the Hudson on the Saratoga and Schuylerville quadrangles, 

 were laid down in its waters. 



Lake Albany was succeeded by Lake A'ermont. The latter lay, 

 for the most part, north of the Saratoga region, in which its 

 deposits are of little importance. In the Champlain valley its 

 waters were lower than those of Lake Albany. 



When the ice finally melted out of the Champlain valley the alti- 

 tude was so much lower than now that the whole of the valley, 

 and of the St Lawrence valley up to Lake Ontario, was below sea 

 level and hence became occupied by marine waters. The whole 

 Champlain-Hudson trough, however, was not thus depressed, 

 Woodworth pointing out that the marine level probably did not 

 reach south of Whitehall. Passing down Lake Champlain the 

 marine beaches, and the marine fossils contained in the deposits, 

 are found at steadily higher altitudes going north. At Plattsburg 

 the marine waters reached a level some 300 feet above the present 

 level of the lake. Woodworth does not believe that the trough 

 south of Whitehall was submerged at this time. The trough seems 

 to have oscillated on a pivot, depresssion at the north being coinci- 

 dent with elevation at the south, and vice versa. The pivotal line 

 lies in the district between Whitehall and Albany. Since the ice 

 vanished, the northern district has been steadily rising, the marine 

 waters have been excluded from the Champlain and the upper St 

 Lawrence valleys, and the St Lawrence estuary now ends at Mon- 

 treal. This upward movement is likely still continuing. - At the 

 same time the lower Hudson valley seems to have been undergoing 

 depression and its estuary lengthening. The Saratoga region is 

 near the pivotal line and probably has been but little affected by 

 these movements. 



We can not leave Pleistocene matters without calling attention 

 to one detail, the impressive glacial boulder shown in plate 20. 

 It stands on the summit of a low drumlin, 3 miles due west from 

 Saratoga, and is a conspicuous object. \'iewed from a distance 

 it looks like a monument, a simple shaft. It consists of a huge 

 slab of Little Falls dolomite about 15 feet long, stood up on end. 

 Some exfoliation has taken place, due to frost attack, but on the 

 whole it has suffered com])aratively little damage from the 



