1922] WATERMAN—PLANT COMMUNITIES ¢) 
morainic uplands. The shore line of the embayment is clearly 
traceable along the southern and eastern border of the Platte Plains 
as shown on the map. On the west the old shore line, protected by 
the morainic ridge, is marked by low rounded knolls, but on the 
south and east it still shows the characteristics of a wave-formed 
bluff (fig. 3). This feature has been continued by wave action in 
the lakes on the south, and it is especially marked on the east, where 
it borders the floodplain of Otter Creek (fig. 7). There it still remains 
asa steep bank rising 150 or 200 feet above the plains. The present 
2.—View toward southwest over shore dunes to morainic ridge which formed 
Fic. 
the Algonquin shore on the sout 
sand ridges with intervening depressions were formed originally as 
sand bars by the receding waters of Lake Algonquin, assisted by the 
winds, which piled dunes of varying heights up to 100 feet above 
Lake Michigan on the successive beaches left bare by the receding 
lake. One morainic fragment is found on the present shore line half 
a mile east of the mouth of Platte River, in shape like a hogback, 
with a very steep forested slope on the south and an equally steep 
bluff of erosion facing the lake (fig. 10). The line of hills between 
Platte Lake and Little Platte is a morainic remnant exactly in line 
with the fragment on the shore. Morainic gravel has been found 
