314 REVIEWS 



tions of glacial phenomena in this portion of the state. Almost the 

 entire region is heavily covered with glacial drift. Very few outcrops 

 of country rock occur. All the moraines of the region show two dis- 

 tinct phases. Above a contour of approximately 200 feet, which marks 

 the upper limit of submergence, they have an irregular rolling surface, 

 while below this line they lose their irregular features and are in fact 

 so subdued as often to be distinguished with difficulty from the ground 

 moraine. These water-laid moraines, however, are distinct though faint 

 topographic features and mark the former position of the ice front as 

 surely as the hilly land laid form. 



In the paper cited a description is given of all the different 

 moraines and beaches formed in this part of the state though the 

 chief interest centers in those found in Sanilac and adjoining counties. 

 In the vicinity of Imlay City a channel occupied by a swamp and 

 bounded by beach lines was discovered extending north and west past 

 this place and North Branch, then southwestward toward Flint. This, 

 called the Imlay Outlet, is regarded as the outlet of a lake (unnamed) 

 at the time the ice foot rested on its northern side. The position of 

 the ice front is marked by a rugged moraine — the Toledo moraine. 



On the retreat of the ice from this position there was next formed 

 the Detroit moraine which, except for a tract near Yale is nearly all 

 water laid. North of Yale near Melvin it is represented by kames and 

 kame moraines. In this area which the author of the paper did not 

 examine we have observed a well-marked series of kame ridges mark- 

 ing the northernmost limit of the eastern limb of the Detroit moraine. 

 Northward the land fades away into the great swamp which extends 

 north from Capac past Valley Center and Brown City to Shabona Post 

 Office and into the almost imperceptible divide between this and the 

 Black River swamp toward the east. 



The last moraine is the Port Huron Saginaw moraine which 

 extends from a point six or eight miles northwest of Port Huron along 

 the east side of Black River to Tyre, thence curving around toward 

 the southwest to Vasser. From the 200 feet contour, around the north- 

 ern and eastern side of this moraine, the land slopes evenly away 

 toward the present shore. West of the eastern limb of this moraine 

 lies the great Black River swamp. 



As the ice front retreated over this swamp region to its last halting 

 stage at the Port Huron-Saginaw moraine, the water from the wasting 

 glacier evidently found its way westward along the ice front, the posi- 



