ste) BOTANICAL GAZETTE [SEPTEMBER 
in at least one spot midway between the two; so it seems probable 
that these represent the remains of a moraine which originally 
bisected the triangle, and which later determined the location of 
Platte River. 
ENVIRONMENTAL CONDITIONS.—The factors of the environment 
are similar to those of the Crystal Lake Bar region (10), and will not 
be repeated here. A study of the soil acidity by WHERRY’s method 
is planned for the near future, and will probably yield interesting 
results. The variations in soil and moisture content are evidently 
3-—View toward the southwest over Platte Lakes, showing Algonquin shore 
Fic 
line in didsace 
of great importance. The substratum consists in the main of 
beach and dune sand, but there is a mixture of morainic material 
around the edges where moraine clay and gravel were washed down 
by the waves of Lake Algonquin and by atmospheric agencies since 
that time. The materials of the low morainic ridge which bisect 
the area are also of considerable importance, and their significance 
will be considered in connection with the migration of the deciduous 
forest elements into the sand ridge vegetation. 
ile the slight moisture content of the superficial layer of 
sandy soil is generally recognized, it has been thought that the 
