8 ON THE FRESH-WATER GLACIAL DRIFT 



Member Number Two. 



This division is not so readily made out as the others, but should not be omitted. 

 In the general section I have not attempted to represent it, except in the space 

 between the Apostle Islands and Flag river, of Lake Superior. It will be more 

 apparent in the local sections. In general, this member is thin, passing into No. 1 

 above and No. 3 below. Its characteristics are, the finer condition of the materials, 

 better stratification, and an alternation of layers of clay and sand. 



Fiff. 5. 



Profile along Bask Strket, Cleveland, Ohio, representing the slides of October, 1849. A. Ancient shore line. 

 C C C. Present shore line and slides, 1849. B B B. Blue laminated clay. D. Coarse sand and gravel. E. Alter- 

 nate bands of clay and sand. 1. Position of cedar trees, leaves and springs. 2. Position of Elephant's grinder. 



At Cleveland, the grinder and a few bones of the Elephas Primigenius were 

 found in D, at a depth of ten feet below the natural surface. The greatest devel- 

 opment of the middle member is seen at the Grand Sable, of Lake Superior, east 

 of Grand Island. Here the layers of coarse sand are exposed with a thickness of 

 300 to 400 feet overlying but a small development of clay. These layers vary 

 from 10 to 50 feet each, having a well-defined stratification. In color, they are 

 bright gray, white, and brown, while their edges cropping out for several miles 

 along the shore, present a more imposing view than the Pictured Rocks. On the 

 summit there is a large tract of treeless and barren dunes, with here and there a 

 clump of pines, nearly covered up by the drifting sand. 



This tract extends southerly across the Peninsula to Lake Michigan, thence 

 across Lake Michigan and down its eastern shore. The " Sleeping Bear" and 

 other prominent sand mountains and dunes on that coast, extending as low as 

 Michigan City, belong to this member of the drift formation. 



Member Number Three. 



The ash colored, the red, and the blue laminated clays, of the general profile 

 constitute this member. A slight diff'erence in the ingredients causes a material 

 difference in their color. The principal cause is the variable proportion of oxide 

 of iron, and its chemical condition. There have not been many analyses of these 

 clays, but the few I am able to give, show that the materials are similar at quite 

 distant points. They are really not clays, but finely comminuted sand, marl, and 



