456 PLEISTOCENE OF INDIANA AND MICHIGAN. 



The hinge line for the Nipissing beach on this shore appears to be at or near Herring Lake, 

 so that places south of Herring Lake are within the area of horizontality. The identity of the 

 beach with one farther south in Michigan, as described by Mr. Leverett, and with its extension 

 around the south and west sides of Lake Michigan, as observed by Leverett, Aldan, and Gold- 

 thwait, seems to be beyond reasonable doubt. In these latter regions it stands in the same 

 relation to the present lake and to the Algonquin beach as does the beach described above in 

 the south part of Lake Huron. (See p. 357.) 



NIPISSING BEACH IN OTHER PARTS OF THE UPPER GREAT LAKES BASINS. 



Since the writer's reconnaissance of 1893 the Nipissing beach has been studied in con- 

 siderable detail on the shores of Green Bay in Wisconsin and Michigan by Goldthwait and by 

 Hobbs. The beach is strong on those shores and is generally easy to recognize. Goldthwait 

 measured its altitude instrumentaUy at many places in Wisconsin and Hobbs at several in 

 Michigan. 



In Ontario the Nipissing beach was not particularly noted by Spencer in his early work. 

 The writer's early investigations in Ontario included this beach at numerous localities, but the 

 more detailed work and the instrumental measurements of its altitude were made by Gold- 

 thwait and the writer in 1908. The beach is developed in great strength along the southern 

 shores of Georgian Bay, especiaUy on the eastern shore of the Saugeen Peninsula and the north 

 shore of the Penetang Peninsula. The region of Lake Simcoe was elevated before the time of 

 the Nipissing beach and was much too high to record it. The beach extends a few nides above 

 Coldwater from the head of Matchedash Bay, but at this village it lies 83 feet below the surface 

 plane of Lake Simcoe. 



The writer's early reconnaissance included observations on the Nipissing beach at many 

 points on the northern peninsula of Michigan and on the south shore of Lake Superior. Since 

 that time Russell and Lane have made some further studies and Mr. Leverett in particular has 

 made a much more thorough investigation. The beach has been found in strong development 

 along the entire stretch of the south shore, except at the west end near Duluth, in which vicinity 

 it appears to pass under the level of the present lake. Mr. Leverett finds it apparently passing 

 beneath the present lake about at Washburn, Wis., on Ashland Bay, and again on the west 

 slope of the Bayfield Peninsula, the greater part of the peninsula showing the mark of 

 this beach. 



In the area of horizontal^ in the basins of Lakes Huron and Michigan the Nipissing beach 

 is about 15 feet above present lake level. The uplift which deformed this beach raised the 

 barrier at Sault Ste. Marie so as to place Lake Superior 20 feet above Lake Huron or about 5 

 feet above the level of the beach in the area of horizontality to the south. From this it may be 

 inferred that if the area of horizontality reaches any part of Lake Superior (and it is obvious 

 that it could do so only at the west end of the lake, where the Nipissing beach descends to or 

 passes below the present lake level), the beach made there before the barrier at Sault Ste. Marie 

 was raised to its present height, supposing open connection at that time with Lake Huron, 

 would now be submerged about 5 feet. This, apparently, is the present condition at the west 

 end of the lake. But, as with the hinge fines in the Lake Huron and Lake Michigan basins, 

 the apparent line here is determined by the backing up of the water, the real hinge being now 

 submerged and lying a few mdes farther south. 



During the time of the full discharge of the Nipissing Great Lakes at North Bay a low stage 

 prevaUed in the region of horizontality, and the beach made then is below the two-outlet Nipissing 

 beach and is now submerged. The same low stage affected the west end of Lake Superior, 

 the lake surface at Duluth being probably 50 . to 60 feet lower then than now, as indicated 

 by the old bed of St. Louis River, now drowned in the bay west of Duluth. In all probability 

 Lake Superior was then separated from Lake Huron by a sluggish river, which was later turned 

 into a strait by drowning during the two-outlet stage, the deformation or tilting now seen in the 

 Nipissing or two-outlet beach comprising only that part of the uplift which occurred after the 

 two-outlet stage had been established. It was therefore this later uplift which produced the 



