ICE RAMPARTS. 



E. R. BUCKLEY, PH. D. 

 Assistant Superintendent Wisconsin Geological and Natural Hiatory Survey. 



The diurnal and weekly changes of temperature during the 

 winter months cause a sufficient expansion and contraction of 

 the ice covering the inland lakes of Wisconsin to shove up 

 the sand, gravel, boulders, and sod along the shores into peculiar 

 ridges, known as ice ramparts. These ridges are of various 

 shapes and sizes, but ordinarily the longer direction extends 

 approximately parallel to the shore. The ridges are discontin- 

 uous, of variable length, and range from a fraction of a foot to 

 several feet, in height. Observations have shown that they are 

 not ordinarily an accompaniment of ve?^ small or very large 

 lakeSj, although their formation is not entirely controlled by the 

 size of the lakes, depending in the region under discussion 

 mainly upon the prevailing climatic conditions. In this state 

 the temperature conditions are such that the formation of ice 

 ramparts is limited to lakes of moderate size, and they are best 

 developed during seasons when the snow-fall is very light. 



During the winter of 1898-99 the precipitation and tem- 

 perature conditions in south central Wisconsin were exception- 

 ally favorable to the formation of ice ramparts by the moderate 

 sized lakes. During this season ridges were shoved up at many 

 places along the shores of different lakes in this region. 



The ice ramparts which attracted the special attention of the 

 author were formed along the shores of Lakes Mendota and 

 Monona. These lakes are located in the south central part of 

 Wisconsin, immediately adjacent to the city of Madison. The 

 general shape and outline of the lakes are sho^vn in Plate L 

 Lake Mendota has an area of 15.2 square miles, and the area 

 of Lake Monona is about 3.9 square miles. The volume of 

 water in Lake Mendota is roughly 16,880,000 cubic feet; that 

 of Lake Monona is very much less. The coast line of both lakes 



