34: WISCONSIN" ACADEMY SCIENCES, ARTS, AND LETTERS. 



lake, soft muck resulting from the annual decay of aquatic vege- 

 tation is accumulating in others. Some of the lakes, especially 

 those not connected with a stream of running water, are thus be- 

 coming rapidly filled with marl and peat, causing changes that be- 

 come apparent after long intervals of time. Some small shallow 

 lakes have thus been changed to meadows within the recollection 

 of the first settlers of the county only 38 years ago. 



The government plats represent some lakes in 1835, which are 

 now only known as marshes or wet meadows. One called " Soft 

 Water Lake," was a clean sheet of water on]}^ four years ago, but is 

 now nearly covered with the leaves of the yellow pond lily (Nu- 

 phar) and other water plants. Soon it will cease to be known as a 

 lake. 



There are also some changes of the level of some of these lakes, 

 indicating a less amount of water than formerly. Sand bars for- 

 merly covered with water are now dry, and in one case the bar extends 

 quite across the lake, thus dividing it into two. Another proof of 

 a diminished supply of water is afforded by the occurrence of an- 

 cient beaver dams in places where no pond could be formed at the 

 present time, for want of running water. 



The time may come when by the use ot some simple, easily worked 

 dredge, the marl, and muck may be removed from the bottom of 

 some of the more important of these lakes, to be used as a fertilizer 

 of the neighboring farms; especially as the beauty of the lakes 

 would be increased by deepening the water, and by the consequent 

 removal of the unsightly vegetable growth along their shallow 

 margins. 



Ice ridges are formed at certain places around the shore, some of 

 them double, or triple, and varying in height up to ten feet. These 

 ridges are formed by the expansion of the ice during the winter, 

 pushing the materials of the beach in-land. They consist of sand, 

 gravel, or boulders; in the latter case they constitute the so-called 

 '' walled lakes." If the banks are high and steep at the edge of the 

 water, no ridge can be formed, but wherever low grounds or marshes 

 approach the lake, they may be looked for. Where springs enter 

 the lake, no ridges are formed, the water remaining above the freez- 

 ing point all winter. Trees are often found with their roots crowded 

 inland by the ice-expansion; their tops leaning over the water. 

 These ridges make excellent road-beds, and are often used for that 

 purpose. 



