GLACIAL AND POST-GLACIAL HISTORY 459 



of levels is made up of a succession of deltas and bar-like gravel 

 ridges, and has a range from about 180 to 200 feet A. T. at the 

 south, and 420 to 450 feet A. T. at the north, down to the level of 

 Lake Champlain (loi feet above sea-level). The upper series of 

 deltas consists of two — an upper and a lower. The upper one was 

 made by the ice waters. The lower was made by the erosion of 

 higher gravels. The one made in the presence of the ice may be 

 absent on some of the more northerly streams. 



Wave-wrought terraces. — Corresponding to these two series of 

 gravel plateaus or deltas there are two series of wave- wrought terraces 

 separated by an interval of about 120 feet at the south and 155 feet 

 at the north. In this interval the terraces are either absent or very 

 faint. 



Upper series of wave- wrought terraces: The upper series of ter- 

 races have been seen at various points from Street Road to West 

 Chazy. They have not been studied north of the latter place. This 

 series of terraces has a range at Street Road and Crown Point of 200- 

 220 feet (520-320 feet A. T.), if certain rather faint terraces be 

 accepted as wave- wrought. The range of terraces at the north varies 

 from 75 feet near Whallonsburg (510 -435 feet A. T.) to 80 and 100 

 feet farther north. On the whole the range increases northward 

 from Whallonsburg, but is still greater at Street Road and Crown Point. 

 Except for the fact that the upper terrace at Whallonsburg and corre- 

 sponding deltas on both branches of the Bouquet River are somewhat 

 lower than at Street Road or Crown Point, the series increases in alti- 

 tude northward. Both series of terraces are best developed and 

 have been studied most a»t places from Port Kent northward. 



In this region the upper series of wave- wrought features is distinct, 

 and, when one's attention has been called to it, is somewhat conspic- 

 uous. The series embraces wave-cut terraces and gravel beach 

 ridges, and in favorable situations bars, spits, and hooks. At places 

 where these features can best be seen they have a range of (i) about 

 80 feet at Port Kent; (2) 80-90 feet one-half mile west of Harkness 

 Station; (3) 77 feet east of Mount iEtna and a httle north, between the 

 latitude of Peru and Schuyler's Falls; (4) 60 feet northwest of Peru a 

 few miles, and nearer Schuyler's Falls than (3) above; (5) south of 

 the Saranac River on the farm of Thomas Riley and a neighbor, the 



