GLACIAL LAKE ALGONQUIN. 



433 



At Colwell and Elmvale the difference is large, and seems to indicate either an error of 

 measurement or a considerable difference of locality. 



Some other altitudes in Ontario are of interest. It is not certain that any of them refer to 

 the highest Algonquin, but it is thought some of them may. The one at North Bay is almost 

 certainly that of a lower member of the upper Algonquin group. 



Altitudes in Ontario. 



a By aneroid barometer. 



Coleman has reported deposits which he regards as beaches at high levels in the region north 

 of the Great Lakes. The highest is 30 miles northwest of Michipicoten Harbor and 70 miles west 

 of Missanaibi. It is described as "a very distinct terrace, of coarse but well-rounded gravel and 

 stones, 1,445 feet above the sea." ' Near the same locality is another sandy terrace at 1,380 feet. 

 Similar deposits are at Gondreau Lake, 20 miles southwest of Missanaibi, altitude near 1,500 feet; 

 near Meteor Lake, 1,420 feet; near Monabasing Lake, 1,335 and 1,316 feet; near Geneva, north 

 of Cartier, 1,400 feet; and 12 miles northwest of Wahnapitae Lake, 1,047 feet. 



It may be doubted whether any of these deposits are true beaches due to wave action in 

 large bodies of water. The descriptions seems to reveal forms which were much more probably 

 formed by glaciofluvial action or were associated with relatively small and local bodies of 

 ponded waters. Nevertheless, some of them may be beaches and may belong to the Algonquin 

 group. It is at least a very singular coincidence that if the plane of the highest Algonquin beach, 

 from Hessel, Mich., to Root River, north of Sault Ste. Marie, be produced northward, it passes 

 the locality at Gondreau Lake at about 1,470 feet. 



In the writer's reconnaissance on the north coast of Lake Superior and in Lawson's more 

 accurate work the highest Algonquin was not certainly identified at any place. 



BATTLEFIELD GROUP OF ALGONQUIN BEACHES. 



MSTRIBL'TIOV 



Mackinac and adjacent islands. — On Mackinac Island next below the upper Algonquin 

 group the surface for about 20 feet is bare or very thinly covered rock, or is a stony bowlder pave- 

 ment. This interval is the surf-wasted zone below the lowest strong strand of the upper Algon- 

 quin group. For 20 feet farther down there are one or two very weak beaches, below which, 

 in the next 20 feet of descent, there are two or three beaches, the upper one of which is generally 

 strong and has some remarkable peculiarities. This is the Battlefield beach. It is called by this 

 name because it was first observed and is most characteristically developed on the battlefield of 

 August 4, 1814, onnorthern Mackinac Island. The locality is now a part of the golf links. The 

 beach forms a strong, beautifully shaped, and even-crested crescentic ridge trending west from 

 some rough knolls of limestone. 



Though in places it contains much sand and fine gravel, this beach in nearly every locality 

 where it has been identified is characterized by unusual coarseness of composition and steep front 

 and back slopes. In some places it looks as though it was formed partly from stones and bowlders 

 shoved up by the ice into something like an ice rampart. Where cut by the road to British 

 Landing it has an uncommonly coarse composition, being made up largely of stones and small 



1 Coleman, A. P., Marine and fresh-water beaches of Ontario: Bull. Geol. Soc. America, vol. 12, 1900, pp. 13S-143. 

 34407°— 15 23 



