420 BOTANICAL GAZETTE 
[JUNE 
is consequently in its surface characters mainly a dune forma- 
tion. A basin or bay-like area formed in the drift clay of the 
glacial period is filled with sand above the water level, the lake 
still occupying a portion of this area. 
The sand forms a dam 
: hf a, Sandy plain 
= Ya oe « 
= “Se y 
: % ‘ Zz Bt 
ey, %~ RY 
a x 
4, 
4, 
¢ x 
s ip Sandy plain. y 
i with clay Subsoi/ a > i. 4%, 
x Te, 
, A mS ts : 
ah ' Clay 
7, 2 z 
/, Sas 
ong Point ; 
e H) se Sandy plain 
= hit? Qi yy 
Sm) W Le" 
My my %, 
=. 4 WY a © %, 
eS wer? = * 
4 SW, yee ; i 
ore IRE Denuded sord >Clay 
with = = 
LZZZDrifting Dunes fy Michillinds Hi % 
TOT Dae ii es Oe, 
oom (/; escarpment TERS eed ae egg ta 
7 a Tp», apDuck Lake amie 
/ = etna) Sandy plain 
: Clay E 
oN oe 
luskrat Late “nay 
4 2 oe 
eer a a ; 
Seale of miles 
Ue ee 
MAP OF THE WHITE LAKE REGION. 
This map is based on one published in The American Geologist (1: 143. 1888), in 
an article “The river-lake system of western Michigan,” 
O 
. W. Wooldridge, M.D- 
nly a few minor changes have been made in the portion of the map used, to indicate 
better some points covered by the present article. 
along the shore of Lake .Michigan and across the outlet of the 
river which impounds the water above. 
Doubtless the small 
lake owes its immunity to filling to these dunes becoming tim- 
bered before the area could be entirely filled, leaving only 4 
river channel. Vegetation crept in from the surrounding 
