19S Bulletin Wisconsin Natural History Society [Yol. 13, No. 4 
The small lakes have little effect on the climate as they are 
soon warmed in summer, and rapidly frozen over in winter. 
Lake Butte des Morts is formed by an expansion of the Fox and 
Wolf Rivers which meet and overflow the land, thus forming a 
large marshy lake. Further up in the courses of these rivers 
other similar expansions are formed, so that there is a continuous 
line of shallow lakes with low, swampy shores extending from Lake 
Puckaway at the extreme north to Lake Winnebago at the south — 
a distance of about twenty-five miles. 
DESCRIPTION OF BOG 
The bog studied lies on the southwestern side of the lake (fig. 
1). It is about three and a half miles long and about a mile in 
width, and covers an area of about one thousand acres, as the 
map shows. Its long axis lies northwest to southeast. The 
shore is met by a very gradual slope with an inclination in most 
places of from three to four degrees. 
Careful observations were taken on a small plot about four 
feet square (fig. 2). This section of bog was situated back of a 
marsh}' area, and was not covered by water. It was, however, 
