G, A, Shufeldt on the Subterranean Sources, etc, 193 
Art. XX.—On the Subterranean Sources of the Waters of the Great 
akes ; by GEorGE A. SHUFELDT. 
Ir we take down the map of North America, and follow 
around the borders of our chain of Great Lakes, we find that 
the tributaries for supplying the mighty torrent of water which — 
pours in immense volumes over the Falls at Niagara, and thence 
through the St. Lawrence to the sea, are few in number and 
insignificant in effect. Lake Superior, the largest body of fresh 
water in the world, has an area of 32,000 square miles and a 
mean depth of one thousand feet. There are a few small 
streams, none worthy of the name of rivers, which find their 
outlet in this lake—the St. Louis and Ontonagon are the largest 
of these; but there is probably not water enough discharged 
into the lake to make up for the atmospheric absorption and 
evaporation. The entire State of Wisconsin, even from the 
Rivers, the waters of which all flow southward, to the Gulf of 
Mexico. The whole State of Minnesota with its thousands of 
lakes and streams may be called the mother of the Father of 
aters—for all of her waters which do not gather into the great 
Red River of the North are discharged into the Mississippi, and 
do not contribute to keep up the supply of Lake Superior; and 
on the northern shore of the lake, in the British possessions, 
there are no rivers which flow in this direction. Here the cur- 
rent is the other way and the streame find their way to Hud- 
son’s Bay and other more northerly seas. The outlet of Lake 
Superior is the River St. Mary’s—a stream of considerable mag- 
nitude—which discharges the surplus waters of the Lake in the 
direction of Lake Huron. Lake Superior is 627 feet above the 
8ea level. 
we examine the surroundings of Lake Michigan we shall 
find the evidences of this theory still more striking. This lake 
aS an area of 22,400 square miles, and a mean depth of 900 
feet. It is above the sea level 578 feet or forty-nine feet below 
Lake Superior. It is also an immense body of water, whose 
sole apparent sources of supply are found in a few small S 
which flow into it from the State of Michigan. pee 
The largest of these are the Grand and Manistee rivers; from 
Wisconsin there is only one small stream, the Milwaukee river 
at Milwaukee. From Illinois there is only the Chicago river, 
a sluggish stream without a current; and indeed there is, at only 
ten miles distance from the banks of the lake south and west, 
