BEACHES OF LAKE DANA. 773 



eeiimile Creek, and thence southwestward past Derby, gravel ridges were 

 observed by the writer and subsequently by Taylor at an altitude of fully 

 700 feet which have both the form and the structure of a beach. These are 

 stronger as well as more characteristic than any of the supposed shore 

 features at the lower levels. (See note on p. 775.) 



Still other places were noted where beaches occur between the Forest 

 beach and the shore of Lake Erie. One of the best defined is at the 

 mouth of Chautauqua Creek, north of Westfield, N. Y. Taylor and the 

 writer found its altitude by Locke level to be 34 feet above the surface of 

 Lake Erie (in August, 1899), or about 606 feet above tide. This is 136 

 feet below the highest Warren shore at Westfield, and about 100 feet below 

 the lowest. There are several places between Westfield and the mouth 

 of Eighteenmile Greek where a weak beach occurs at altitudes ranging 

 from 35 to 60 feet above Lake Erie. These were examined by Taylor and 

 the writer in 1899, and were at first thought to mark a single shore which 

 rises more gradually toward the northeast than the shore of Lake Warren. 

 But upon further reflection and a correction of barometric determinations, 

 by means of the topograplaic maps of that region, it seems quite as probable 

 that they are merely incidental shore phenomena of a falling lake. 



In view of the fragmentary character and the lack of harmony in 

 level presented by these weak shore lines on the borders of the Erie Basin, 

 it will probably be a difficult matter to establish satisfactorily the extent of 

 Lake Dana or the equivalents of the Greneva beach. 



The lowering of the lake level from Lake Dana to Lake Iroquois 

 seems to have been accomplished by the withdrawal of the ice sheet and 

 the uncovering of successively lower channels leading towai-d the Mohawk 

 Valley. Fairchild states that the district from 15 miles southwest of 

 Syracuse to 12 miles east was apparently the critical region, because a 

 broad expanse of the low Ontario plain (400zb; see PL I) meets abruptly 

 the elevated plateau, and here the ice bodyjingered in its last efi'ort to dam 

 the Huron-Erie-Ontario waters from the Mokawk-Hudson Valley. But as 

 yet the full succession of events and the relationship of channels subsequent 

 to Lake Dana have not been determined. The history is partially obscured 

 in the low Syracuse district by the changes in hydrography which have 

 occun-ed since the ice removal. These, as stated by Fairchild, are (1) 

 the possible existence of a pre-Iroquois water body with elevation toward 



