a well that was about six feet in diameter and 

 four feet in depth. Seepage filled this hole, and 

 into it he piled a number of green aspen chunks 

 and cuttings, a meagre food-supply for the long, 

 cold winter that followed. Extreme cold began 

 in early November, and not until April was there 

 a thaw. 



Before the lake-bed was snow-covered, all the 

 numerous canals and basins which the beaver had 

 excavated could be plainly seen and examined. 

 The magnitude of the work which the beaver had 

 performed in making these is beyond compre- 

 hension. I took a series of photographs of these 

 excavations and made numerous measurements. 

 To the north of the house a pool had been dug 

 that was three feet deep, thirty feet long, and 

 about twenty wide. There extended from this a 

 canal that was one hundred and fifty feet long. 

 The food basin was thirty feet wide and four feet 

 deep. This had a canal connection with the house. 

 In the bottom of the basin was one of the feeble 

 springs which supply the lake. Another canal, 

 which extended three hundred and fifty feet in a 

 northerly direction from the house, was from three 



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