382 Wisconsin Academy of Sciences, Arts, and Letters. 
the water is best seen on cloudy days; but even at other times, when 
most lakes reflect the blue of the sky, the surface of this lake is 
often a bright green. The same color is very noticeable when one 
is beneath the surface. The lake floor is in most places covered 
with a fine marl. 
These conditions afford an interesting comparison with those in 
Lake Mendota. The waters of the latter are less transparent and 
warmer than those of Green Lake, and the bottom is of mud. 
There are striking differences in the underwater vegetation of the 
two lakes, which may be correlated to some extent with these en¬ 
vironmental differences. 
Various types of shore are found in different parts of Green 
Lake. Along most of the north side of the lake the land ends in 
smooth boulders of considerable size, behind which the shore slopes 
steeply upward for a short distance (fig. 1). A beach of smaller 
stones runs out a considerable distance beneath the water. To¬ 
wards the northwest corner of the lake rises the hill known as 
Sugar Loaf (see the accompanying map), whose steep sides de¬ 
scend below the surface of the water at almost the same pitch, 
broken only by a narrow rocky beach at the water’s edge. The 
opposite shore of Norwegian Bay, and a long stretch of the south 
shore of the lake (fig. 2), descend even more steeply into the water, 
and consist largely of more or less sheer rock walls. At both ends 
of the lake are wide sandy beaches, backed by gently rising mead¬ 
ows. Finally, at the mouths of the various streams that enter the 
lake, and around the outlet in Dartford Bay, there are extensive 
swamps and marshes (fig. 3). At the head of Norwegian Bay is 
found a muddy bog. 
In general the shore line is very similar to that of Mendota, with 
the difference that the sandy beaches of the latter are much more 
extensive. 
As in Mendota, the shore line is paralleled by a belt of sub¬ 
merged attached plants, extending in an unbroken line all around 
the lake. In Green Lake, however, this flora differs widely in 
nature and distribution from that of Mendota. The wide sandy 
beaches are not nearly so well covered. The rocks of the shore are 
nearly destitute of the tufts of Cladophora that are so character¬ 
istic of Mendota. The main axis of the lake lies parallel to the 
southwest winds that prevail in summer, and the consequent vigor¬ 
ous action of the waves is perhaps partly responsible for these 
