CHAPTER XX. 



GLACIAL LAKE LUNDY (LAKE DANA, LAKE ELKTON) AND THE TRANSITION TO 



LAKE ALGONQUIN. 



By Frank B. Taylor. 



HISTORY. 



When the waters fell from Lake Warren they rested first at the Grassmere beach and later 

 at the Lundy (Dana, Elkton), which is a weaker strand at a slightly lower level. Both of these 

 beaches are horizontal to a point a few miles north of Black River in northeastern St. Clair 

 County, but north of that they rise gradually at least as far as the outer part of the "thumb," 

 where they turn westward into the basin of Saginaw Bay. The Grassmere splits northward 

 with increasing vertical intervals between the separate strands and the Lundy splits in less 

 degree. These splittings show that sharp differential elevation of the northern part of the 

 "thumb" took place during the building of these beaches. 



During the time of the Grassmere beach the waters of the Lake Huron and Lake Erie 

 basins were connected by a shallow strait, which varied greatly in width and at one or two con- 

 stricted points was so narrow and shallow that it may have had a slowly flowing current, though 

 not one sufficient to constitute it a river in the ordinary sense. (See PI. XIX.) 



When the waters fell to the level of the Lundy beach they flowed for a brief time with a 

 strong current (as shown on fig. 10) over the top of the main moraine of the Port Huron system 

 at St. Clair, 1 1 miles south of Port Huron. (See pp. 474-475.) As the moraine was composed of 

 unconsolidated drift materials, it was soon cut through and Lake Lundy came to one level on 

 both sides with its outlet near Syracuse, N. Y., and is therefore not to be regarded as an early 

 stage of Lake Algonquin. Later, when Lake Lundy began to fall, two other barriers made 

 their appearance, one at Detroit (the Detroit interlobate moraine) and the other near Trenton 

 and Amherstburg. The latter was composed largely of ordinary till or bowlder clay, but partly 

 of closely packed bowlders and partly of bedrock. The present channels through this ridge 

 are in till, but the main channel, which passed originally close along the east side of Grosse 

 Isle, resting on bedrock around Stony Island, has now shifted farther east, where the rock 

 surface is lower and the bottom is hard, very bowldery till. 



The uncovering of these barriers brought St. Clair and Detroit rivers and Lake St. Clair 

 into existence and inaugurated Lake Algonquin, the largest of the glacial lakes in the Great 

 Lakes region. 



The studies in the Niagara region have shown that Fairchild's Dana beach and Spencer's 

 Lundy beach are the same. As the name Lundy was applied at an earlier date it is adopted 

 here. 



OUTLET. 



The outlet of Lake Lundy has not yet been determined by continuous tracing of the beaches 

 into close connection with it, but Fairchild x has shown that during the time of the Lundy or 

 Dana beach it was in all probability through the great Marcelhis-Cedarvale channel winch 

 crosses the front of the hills southwest of Syracuse, N. Y. It is certain that the outlet was not 

 by the Grand River channel to Lake Chicago, for the divide at the head of that channel has an 

 altitude of 653 feet and was within the area of horizontality, in which the Grassmere beach has 

 an altitude of 640 to 645 feet and the Lundy beach is about 20 feet lower. It seems clear 

 ' also that the outlet was not northwestward to Lake Chicago along the hills northwest of 



1 Fairchild, H. L., Glacial waters in the Lake Erie basin: Bull. New York State Mus. No. 106, 1907, p. 44; Glacial waters in central New York-. 

 Bull. New York State Mus. No. 127, 1909, p. 53 and PI. XL. 



