PHYSIOGRAPHY. 35 



Tlie combined effect of the di-aining and filling has been to sepai'ate 

 what was formerly a long narrow lake trending NE-SW. into three rounded 

 bodies of water, two of which are connected with each other, the larger of 

 these two and the third lake being connected with the main stream by very 

 short necks. An artificial dam has been built across the narrow channel 

 below the lakes, and the effect has been to flood the delta and unite the 

 lakes into one large body of water, occupying, approximately, the area 

 covered by the glacial lake, thus restoring the conditions which existed 

 before the natural barrier had been trenched. 



In the remainder of the course of the Deer River the tendency of other 

 artificial dams to restore the river to its original condition, that of a series 

 of connecting lakes, is well shown. These dams were built by lumbermen 

 at the foot of the lakes or swamps when it was desired to retain a large 

 body of water at these places. When, on the other hand, the desire was to 

 enable the logs to j^ass rapids, a dam (marked B on the map) was built near 

 the head of the rapids. The back water would bring the logs to the dam, 

 and on opening the gates the flood would carry them over the rajjids into, 

 the deeper water beyond. The Deer River thus, after having reached a 

 somewhat advanced stage, has been rejuvenated by the Michigan lumbermen. 



A study of the small tributaries shows the same condition of things, 

 although not on so larg-e a scale nor so perfectly as in the main stream. 



The source of the Deer River is in the copious springs which rise out 

 of a spongy, marshy piece of ground less than 125 yards distant from 

 Bone Lake, and about 20 feet below the usual water level of Bone Lake, 

 and are really fed by the lake water percolating throiigh the drift and 

 appearing at this point. From the springs there is a depression which leads 

 up to the lake. The highest point of this depression was about 3 feet above 

 the normal water level of the lake. 



The outlet of Bone Lake is the Fence River. The river leaves the 

 lake at a point three-quarters of a mile distant from the head of the Deer 

 River Valley. In order to obtain a supply of water for driving the Fence 

 River, Bone Lake has been couA^erted into a reservoir. A dam was built 

 at the outlet which raised the water about 4 feet, and the result was to turn 

 some of the water of the lake into the Deer River, necessitating also a dam 

 across this small valley near the lake shore. At present oulv a few strokes 

 of the shovel would be necessary in order to turn the water of the flooded 



