A RECONSTRUCTION OF WATER PLANES 



475 



corresponds with that part of Diagram 6. The remaining part, north 

 of the Trent outlet, covers a large field in which studies have been 

 less detailed and the reconstruction on that account cannot be regarded 



Fig. 5. — Diagrams showing how the water planes of Lake Algonquin and the 

 Nipissing Great Lakes should be related, as seen in profile, if the generally accepted 

 history of the lakes is correct, i, 2, 3, 4, 5, 6, six selected stages in the lake history 

 during the retreat of the ice border and the differential uplifts. X, the point on which 

 the differential uplifts hinged, Onekama. The triangles represent outlets, the con- 

 trolling point being the apex. P. H., Port Huron outlet. T, Trent outlet. N, 

 Nipissing outlet, a, b, c, d, e, etc., successive water planes of the lakes, in the order of 

 their age. a, early Algonquin beach, unknown in the Michigan basin, but theoreti- 

 cally necessary in the Huron basin, b, c, planes of temporary low water stages through 

 the Trent outlet; d, plane of the "Algonquin beach;" e, plane of the Battlefield beach 

 /, plane of a Fort Brady beach; g, plane of a temporary low-water stage through the 

 Nipissing pass, possibly marine submergence; h, plane of the Nipissing shore line; 

 i, plane of the Algoma shore line; j, present plane of the Lake Michigan. 



