94 • NEW YORK STATE MUSEUM 



The inequalities seldom show at the surface owing to the conceal- 

 ing mantle of morainal and alluvial materials; the tops of the 

 ridges may be seen occasionally to rise a few feet above the general 

 level, disappearing again with a slope that is more rapid to the 

 east and west than north and south on the line of their axes. 



Present Topography 



The clays and sands within the valley have a distinctly terraced 

 form when the beds are viewed from a point near the river or 

 when their bounds are traced on a topographic map. The original 

 flat contours, a sequence of their disposition in open waters, have 

 been modified more or less by wind and stream erosion, which 

 has been particularly effective upon the soft, fine Lake Albany 

 sediments ; yet the terraced arrangement is still well shown, indeed 

 lends the most characteristic feature to the topography along the 

 river north of the Highlands. 



The terraces front the river as a series of bluffs and sloping 

 banks, that are dissected here and there by lateral stream channels. 

 They are present, though not developed evenly throughout, as 

 far as Fort Edward, near the junction with the Champlain valley 

 which begins across a low divide just north pf that place. Similar 

 terraces occur in the Champlain valley, and it is considered probable 

 by Woodworth that the waters of the two basins were confluent 

 during a part of the period when the sediments were laid down. 



In altitude, the terraces fronting the river range from 40 or 50 

 feet up to 200 feet. The lower elevations mark those formed as 

 outwash plains and lateral moraines while the ice was still 

 present in the valley. They are to be seen in the section in the 

 Highlands southward, beyond the limits of the clay terraces of 

 Lake Albany which extended only as far south as Kingston. The 

 Lake Albany terraces where they front the river have their upper 

 surfaces mostly at 150 or 200 feet above tidewater, rising slightly 

 above the top of the rock gorge and thence extending outward over 

 the valley floor. In the widened section of the lake near Albany 

 the terraced beds extend back to Schenectady where they lie at an . 

 elevation of about 400 feet, and well-marked flats at that altitude 

 are found west of Round lake, which seem to belong to the same 

 series of deposits. These higher levels are floored with fine sands, 

 whereas the clay does not appear to reach above 250 feet and is 

 mainly below the 200 feet contour. 



The fine sands that mantle the clays have been worked over and 

 redistributed by the winds, as stated in a previous paragraph, so 



