CASTOROI.OGIA. 75 



ing the subject we will quote the remarks of Mr. S. F. Baird, 

 one of America's best informed naturalists ; he says : " In my ob- 

 servations I have never seen the beaver lodge assume the marvelous 

 features usually ascribed to it, and any I have met with can only be 

 described as resembling an irregular pile of wood cuttings. ' ' Cer- 

 tainly anything approaching the exquisite beauty of workmanship 

 which the common birds of our neighborhood display, need not be 

 looked for, and in comparison with the nest-building accomplish- 

 ments exhibited by the Oriole {Icterus Baltimore), the domestic 

 arrangements of the beaver must be ranked among the ordinary 

 works of lower intelligence. 



•But there are still points to consider in which the character of 

 the beaver becomes most digniiied, and the closer these matters are 

 studied, the more admiration and wonder they excite. A beaver 

 dam examined in the most matter of fact way, introduces a chain of 

 thought destined to raise our esteem of the animal to the highest 

 degree. Why should a dam be constructed at all ? Undoubtedly, 

 the object of the dam is to secure more water, and to preserve it for 

 use through seasons when a natural supply cannot be relied on, and 

 simple as the case may appear, it involves some most interesting 

 points of hydraulic engineering, and presents not a few problems for 

 discussion. 



In the first place the beaver's power of transporting materials is 

 decidedly limited, and therefore the dam mast be built mainly of 

 such stuff as the locality readily affords ; so that besides the familiar 

 form constructed chiefly of branches (as in the beaver enclosure on 

 the Marquis of Bute's estate), there are grass, sand and mud struc- 

 tures, the last of which is depicted in the frontispiece of this volume. 



The best explanation of what might have constituted the primi- 

 tive form, is the circumstance of the felled tree blocking the stream, 

 and in itself practically forming a dam, for the ordinary drift of the 

 stream would soon fill in the smaller interstices, and thus the level 

 of the water would be raised and maintained, answering every re- 

 quirement of the colony. But there is an immense advance on this 



