GLACIAL LAKE ALGONQUIN. 



431 



On the west side of Lake Huron between Mackinac Island and Port Huron the highest 

 Algonquin beach has altitudes as follows: 



Altitudes of highest Algonquin beach on the west side of Lake Huron. 



Mackinac Island . 



Rogers 



Crawford's quarry 



Posen 



Alpena 



Ossineke 



Harrisville 



Greenbush a 



Tawas 



Omer 



Worth 



Kawkawlin& 



Bavporta 



Seliewaing 



Bridgeport 



Port Austin a 



Grindstone City " 



Port Sanilac a 



Port Huron a 



Goldthwait. 

 Gregory. 



Leverett. 

 Gregory. 



Do! 

 Cooper. 

 Lane. 



Do. 

 Cooper. 

 Gilbert. 

 Taylor. 



Do. 



Do. 



a Determined by hand level. All are in situations very favorable for obtaining accurate results with this instrument, each of them involving 

 only five or six short sights. 



b The extra height of 3 or 4 feet here is in all probability due to wind-blown sand. 



On the west side of Lake Michigan the altitude of the highest Algonquin beach has been 

 determined as follows (see PI. XXIV) : 



Altitudes of highest Algonquin beach on west side of Lake Michigan. 



Burnt BlulT, Midi . 

 Deaths Door, Mich . 

 Rowleys Bay, Mich 



Oconto, Wis 



Sturgeon Bay, Wis. 



Cormier, Wis 



Algoma, Wis 



Two Rivers, Wis. . . 



Evanston,Hl 



Rogers Park, 111.... 



On the south side of Lake Superior a few measurements of the highest Algonquin, besides 

 those at Sault Ste. Marie and Kexford, have been made by Mr. Leverett. Back of Houghton 

 its altitude is 1,040 feet (aneroid), or about 440 feet above Lake Superior, and at Calumet it 

 is 1,090 feet, or 490 feet above Lake Superior. In the Marquette quadrangle it lies near the 

 940-foot contour, and near Munising it is 953 feet, by wye level from Wetmore. On St. Joseph 

 Island it is 934 feet as measured by Mr. Leverett by wye level. 



In the western part of the Lake Superior basin — in fact, from the outer part of the Keweenaw 

 Peninsula west — a number of beaches belonging to Lake Duluth and lower waters he above those 

 of Lake Algonquin, from which they have not yet been clearly differentiated. A further diffi- 

 culty in the western part of the basin on the south side is the fact that a considerable part of 

 the slope is covered with lake clay without pebbles or gravel and the beaches appear only as 

 irregular and faintly cut benches. 



As will be pointed out later, the hinge line of the Nipissmg appears to pass across the west 

 end of Lake Superior. If the Algonquin beach maintains the same relation to the Mpissing 

 here as in the Lake Huron basin it would come to a horizontal attitude at the same line and would 

 then descend nearly to present lake level at Duluth. But on the facts now available this seems 

 improbable. 



