Beaver 457 



high, 1 8 feet wide at base; holding the water above it at 5 

 feet higher than in the pool below. 



This dam must have contained about 250 tons of material. 



The dam which makes Beaver Lake in Yellowstone Park 

 I believe is the longest ever recorded. I saw it from a distance, 

 but had no opportunity of measuring it. General S. B. M. 

 Young writes me that it is about 700 feet from end to end. 



Reference to the plan (Fig. 129) shows a great many little l/\nd- 

 docks or landing places. These are short canals with raised places 

 mud or sod wharfs at the end; these are either lookouts or 

 sunning places. Usually there are paths leading away from 

 them farther afield. They are found chiefly on the western 

 side, as there is no food on the eastern bank. 



The dock seems to be the small beginning out of which 

 grew what some consider the Beaver's most wonderful achieve- 

 ment — the canal. 



The canals are quite as interesting as the dam; Morgan theca- 

 considers them even stronger evidence of intelligence. He ' 

 says:'" "In the excavation of artificial canals as a means for 

 transporting their wood by water to their lodges, we discover, 

 as it seems to me, the highest act of intelligence and knowledge 

 performed by Beavers. Remarkable as the dam may well be 

 considered, from its structure and objects, it scarcely surpasses, 

 if it may be said to equal, these waterways, here called canals, 

 which are excavated through the lowlands bordering their 

 ponds for the purpose of reaching the hardwood, and of 

 affording a channel for its transportation to their lodges. To 

 conceive and execute such a design presupposes a more com- 

 plicated and extended process of reasoning than that required 

 for the construction of a dam; and, although a much simpler 

 work to perform, when the thought was fully developed, it was 

 far less to have been expected from a mute animal." Many 

 canals in all stages of growth are shown on the plan (Fig. 129), 

 but the largest and most interesting is the 70-footer, leading 



'" Ibid., p. 191. 



