THE PELHAM LAKE AND ESKEE. 583 



Up to this point the section, after reaching the sand, has crossed tlie 

 plain of the Orient House (shown in fig. 32, p. 578), a plain whose surface 

 has been produced by a later erosion. The sands exposed in the cutting, 

 however, are a part of the entrance terrace, and their irregularity seems 

 due to their deposition against or upon a shifting barrier of ice. 



C. — From here the section continues at the level oi this plain along the 

 north slope of the notch cut by the brook in the portal terrace, about 40 

 feet below the surface and 60 feet above the brook, and for a long distance 

 runs in clean-washed, very tine white sand, laid horizontally in broad, flat 

 lenticular masses, 1 to 6 inches thick and many feet long, with clayey 

 boundaries which projected on slight weathering-. It preserves everywhere 

 its original delicate structure undistui-bed. 



Eastward the hill is cut down by erosion and the ditch sinks on its side, 

 showing these tine sands to be in great force and to rest upon till, through 

 which the ditch passes a short distance and rises along the side of a second 

 hill and continues in the sands. There was exposed the following section : 



1. Below, a very fine white sand, in layers 4 to 6 inches thick, which 

 ran with very slight undulations for 20 feet or more, and, thinning out, were 

 replaced by others. This was exposed in a thickness of 1 to 2 feet. 



2. Above, for 2 feet, was the same fine sand, but showing a most deli- 

 cate and beautiful flow-and-plunge structxu-e, the laminae dipping 20° E. 

 Above, this sand is limited by an imdulating surface of erosion ujion which 

 rests — 



3. Two feet of coarser sand, slightly i-eddish, with sharp regular cross 

 bedding, which dips 30° E. By the weight of the sliding bank above, this 

 has been compressed into curious corrugations. 



The ditch rises and sinks in the steep hillside, and the lower horizontal 

 sands (1) can be traced for 40 rods eastward and are present in considerable 

 thickness. The coarser sands (2) extend probably to the top of the hill, 

 about 30 feet. 



A specimen of the sand taken from the lowest bed (1) was, when 

 dried, like the finest corundum flour, and consisted of sharp, transparent 

 quartz grains 0.03 to 0.04"™ in diameter, with here and there a scale of 

 wine-yellow biotite. 



The flow-and-plunge stnicture of the upper portion of the tine sand, 

 dipping to the east, indicates a current coming trom the west, and to this 

 current we may attribute the erosion which prepared the surface upon 



