142 Wisconsin Academy of Sciences, Arts, and Letters. 



is irregular. In some places the lakes are bordered by low 

 swamp lands, while at other places the land juts out into the 

 lake, forming vertical, or nearly vertical escarpments, thirty 

 or forty feet in height. The bank is in some places vertical, or 

 even overhanging, while in other places it slopes very gradually 

 to the lake. The banks of the lakes consist of horizontal beds 

 of limestone and sandstone, sand and gravel, boulder clay, 

 and marly ooze and weeds which pass shoreward into marsh- 

 grass meadow-land. At many jDlaces the banks are covered with 

 trees down to the water's edge. This great variety of shore con- 

 ditions furnishes a corresponding variety in the shape of the 

 ice ramparts, resulting from the shoving of the ice. 



According to the records of the Madison Democrat,^ Lake 

 Mendota closed on the 7th day of December, 1898, while Lake 

 Monona remained open until the 12th. During the winter 

 which followed very little snow fell in the region under consid- 

 eration, and during a greater part of the season the ice on the 

 lakes was bare. The temperature changes during the months of 

 December, January, and February were very great, as is sho^vn 

 by the accompanying table, which was compiled from the rec- 

 ords of the Washburn Observatory. The season was one of al- 

 ternating warm and cold spells. Several warm spells were fol- 

 lowed by periods of intense cold ; the changes being very rapid 

 and extreme for this region. During three days of the latter 

 part of December, the thermometer fell 54° F., or from +42^ 

 to — 12° ; during four days in the latter part of January, the 

 temperature changed 55° F., falling from +30° on the 26th to 

 — 25° on the 29th; from the 12th to the 15th of February the 

 temperature changed 61°, rising from — 30° on the former day 

 to +31° on the latter. Many other temperature changes occurred 

 during this period but these were the most marked. 



^This record is taken as authority because it corresponds with observations 

 made by the author. 



