GLACIAL LAKE ALGONQUIN. 443 



Huron, passes about halfway between Dunkirk and Silver Creek, N. Y., and about 30 miles 

 southwest of Buffalo. On the " thumb " in Michigan the Warren beach at this line has an altitude 

 of about 755 feet, or about 75 feet above its horizontal, undisturbed part. Two miles northeast 

 of Sheridan, N. Y., on the same line produced, the Warren beach has an altitude of about 760 

 feet, or about 80 feet above its horizontal part; that is to say, it is uplifted about the same 

 amount as at the Algonquin hinge on the "thumb." It is not known, however, that the Algon- 

 quin hinge line touches this point in New York; and on the other hand, it is not known that all the 

 uplift at this place is of pre-Algonquin age. If the Algonquin hinge line produced to the south- 

 east bends out of' a straight course before reaching Sheridan, it is more likely to bend to the 

 north, in harmony with the isobases of the Iroquois water plane, than to the south. 1 This would 

 indicate a slightly larger pre-Algonquin uplift along the hinge line in New York than on the 

 "thumb," but the difference is probably small. Fairchild finds the uplift farther northeast to be 

 about 2 feet to the mile. This, if continued to the 80 feet of uplift near Sheridan, would make 

 140 feet in all at Buffalo. This is oidy approximate, but it is the best estimate now available 

 for the amount of uplift at Buffalo before the beginning of Lake Algonquin. It would give the 

 Warren beach at Buffalo an altitude of about 820 feet. At Alden, 20 miles east of Buffalo, 

 however, it is 845 to 850 feet, the direction of greatest rise being only a few degrees east 

 of north. 



Facts in two areas bear indirectly on the amount of uplift at Buffalo during and after the 

 existence of Lake Algonquin. On the west side of Saginaw Bay the Algonquin beach rises about 

 18 feet in 30 miles up the tdted water plane from the hinge line. This represents the combined 

 Algonquin and post-Algonquin uplifts. The rate is slightly less for the same distance north 

 from the hinge fine on the two sides of Lake Michigan, and it is slightly greater on the east side 

 of Lake Huron, the rate apparently increasing gradually eastward. Data derived from the 

 Iroquois beach in the basin of Lake Ontario will probably be helpful in the future, but are not now 

 available. If the assumed position of the hinge line in New York is not wide of the truth, and if 

 the rate of rise is about the same or slightly greater than on Saginaw Bay, it may be said that at 

 the beginning of the Algonquin uplift the outlet at Buffalo was somewhere between 15 and 25 

 feet lower than now, and that the uplift caused this much drowning in the western part of Lake 

 Erie. This seems to show that the greater part of the deformation of the basin of Lake Erie, 

 say 110 or 120 feet of uplift at Buffalo, was before the time of Lake Algonquin, and before the 

 independent stage of Lake Erie. Hence, only a little additional uplift during and after the 

 existence of Lake Algonquin was required to bring the waters nearly to the present level of Lake 

 Erie and very nearly to the plane of the drowned shore described by Moseley. (See p. 462.) By 

 the best estimate now available this amounted to 20 or 30 feet. 



FORT ERIE BEACH. 



In 1907 the writer found a strong old shore line, the Fort Erie beach, extending westward 

 along the Lake Erie shore from Fort Erie, Ontario. It is a gravel ridge in Fort Erie and is 

 strong at intervals as far west as Lowbanks, beyond which it has not been traced. It is nearly 

 horizontal, standing 14 to 15 feet above the lake in Fort Erie and only 4 or 5 feet lower at Low- 

 banks, 28 miles to the west. This beach is distinctly old, is considerably weathered, and is 

 generally preserved only on rocky parts of the shore, where it could not be undercut by later 

 wave action at lower levels. At Lowbanks it is a little lower than the modern storm beach. 

 This beach confirms Fairchild's conclusion that the direction of tilting in the eastern part of 

 the Lake Erie basin is more nearly north than it is farther west. 



The Fort Erie beach has not yet been identified farther west or southwest, but it seems 

 probable that near the Algonquin hinge line, about 30 miles southwest of "Buffalo, it becomes 

 horizontal 15 to 25 feet below the present lake level and so continues westward. It is perhaps 

 possible that the Fort Erie beach corresponds to the submerged shore fine found by Moseley 

 at the west end of the lake, but it is probably more deeply drowned. This beach is almost 



i See Goldthwait's isobase map: Bull. Geol. Soc. America, vol. 21, 1910, p. 233. 



