‘outhwest, there are extensive plains covered with shallow water. 
The bottom, in the depression toward the lake and where the 
Miiatic vegetation is only at its origin, is sandy clay. But, in 
‘Memore shallow places, the clay is already muddy and blackened 
prince by the detritus of the herbaceous vegetation which 
Sgtown upon it. Farther toward the borders, and in propor- 
‘lotto the shallowness of the water, the detritus thickens, and 
‘‘Silfarther, we have wet prairies, with exactly the same vegeta- 
ton as that of the lake swamps, and a black soil with a substra- _ 
Peet clay , the same materials also as those of both the deeper 
Spy shallow swamps of the lakes. In receding from th 
_ Mets of the lake toward the high prairies, the transition from 
Netto dry prairies is by so insensible degrees that it would be 
ite appearances are the same. Vegetation is here and there 
: Nodified by the presence of some peculiar species of herbaceous 
: Hants, by 
dn my letter ¢ ag I have omit- 
my letter to P. : ‘on is discussed at length. a 
: Hhere the d : Teg Tao bap os for the elucidation of the subject. 
