REPORT OF THE DIRECTOR I9II 33 



stronger portions of the Iroquois beach, notably a stretch of about 

 ten miles in the town of Lawrence, St Lawrence county. In contrast 

 some sections require close examination to determine the upper 

 limit of wavework. 



The declination of the shore line from Franklin, Quebec, to 

 Potsdam, N. Y., and on to near Watertown, is slightly less than one 

 foot a mile. On the east side of the Covey hill salient, in the 

 Champlain valley, the beach declines at the rate of about three feet 

 a mile in direction some 20 degrees east of south. The isobars seem 

 to lie about 10 degrees south of west, which makes the direction of 

 steepest uplift about 10 degrees west of north. This explains the 

 nearly level attitude of the beach in Canada. 



The Iroquois shore is now approximately known throughout its 

 reach from Covey gulf to Watertown, being located chiefly by the 

 heavy deltas on the principal streams, but with good bars or shore 

 line features at several localities. The deformation of the Iroquois 

 plane in northern New York is 2.4 feet a mile in the southwest 

 direction, using the highest bar at Watertown (733 feet). Using 

 the lower series of bars (671 feet), which probably represents the 

 later or Covey gulf plane, the deformation is 2.9 feet a mile. The 

 beach is nearly parallel to the marine shore, the intervening distance 

 being five to seven miles. 



Between the Iroquois and the marine planes are two other water- 

 levels. The continuity and importance of these intermediate planes 

 was first recognized by Professor Chadwick, who has specially 

 studied them on the Potsdam and Canton quadrangles. The 

 explanation of these lakes necessitated reexamination of the slopes 

 of Covey hill and study of the Pleistocene features in the Champlain 

 valley. 



It appears that the waning Labradorian ice sheet lay close about 

 the Covey hill promontory, as if reluctant to yield its hold on New 

 York. Because the flow movement was from the northeast the ice 

 body pressed with more force on the east side of the salient, so that 

 when the Iroquois waters, creeping northward in the St Lawrence 

 valley between the ice border and the Adirondack highland, 

 finally reached the low pass across Covey hill, they found 

 the ice still closely investing the Champlain side of the highland. 

 The outflow at Covey gulf, successor to or contemporaneous with 

 the Rome outlet, was held up at high levels and produced heavy 

 and characteristic iceborder drainage phenomena. A river as large 

 as the St Lawrence, with ice for its eastern channel wall, flowed 

 southeast across the towns of Mooers, Altona and Beekmantown 

 and stripped large areas of Potsdam sandstone bare of drift, as 

 described by Woodworth in his papers on the Mooers quadrangle. 

 In its earliest flow the Altona river (as we propose to call the flood) 

 had very little fall at Covey hill, but curved southeast and then south 

 some eight miles to the valley of the north branch of the Big Chazy 

 river, then southeast and south some fifteen miles until it poured 

 its flood into the glacial Lake Vermont (named by Woodworth) at 



