l6o MAMMALS OF PENNSYLVANIA AKD NEW JERSEY. 



below the original surface of the bluff and fifteen feet higher than the creek. 

 Its horizontal diameter at that point was nearly two feet, its vertical diameter 

 somewhat less. It descended, at an angle of 45 degrees, toward the edge of 

 the marsh, but I failed to find an opening, either above or below the water, 

 at the point indicated. The walls of this tunnel were quite smooth at the 

 sides and bottom and arched throughout with wonderful regularity of outline 

 and dimensions, and exposure to the air had so hardened the clay matrix as 

 to give it the appearance of having been chiselled through rock. The other 

 opening lay at about the same level, fifteen feet to the right of the first. It 

 was smaller, more circular, and seemingly represented a branch from the 

 other, appearing to join it at an acute angle, about ten feet from the edge of 

 the marsh. Its diameter was about ten inches, too narrow to allow two large 

 otters to pass by each other. From the appearance of these excavations I 

 was sure they belonged to no animal whose home I had hitherto examined, 

 and after a short search was so fortunate as to find the foreman of the brick 

 works, who had engineered the entire * diggings.' The first intimation he 

 had of the presence of otters in this locality was the discovery of a large hole 

 in the bottom of the creek, where it now runs through the swamp, seventy 

 yards from its former channel, against the bluff occupied by the burrow. 

 Otters had long been reported as frequenting the creek, but he had never 

 seen them. The occasional loud splashing and growls of an animal (not a 

 muskrat) in that spot, however, confirmed his suspicions that the hole in the 

 creek bottom was still frequented by these wary fishermen. Not long after, 

 as his men were digging through the bluff, they broke into a large chamber, 

 ' big enough to hold a horse and cart.' This was located six feet below the 

 surface and about forty feet from the edge of the bank. It terminated the 

 smaller burrow, previously alluded to as number two. 



" Subsequent digging, a year or two later, showed that burrow number one 

 soon diverged far to the right of the point where I had examined it, and 

 terminated, at a depth of twelve or fifteen feet below the top of the bluff, in 

 an oval chamber, much smaller than the other, about six feet long and three 

 feet high. This arm of the Y was much the longer of the two, reaching sixty 

 or seventy feet from its junction with the first. The tunnel leading to it was 

 more than twice the size of that leading to the larger chamber. The man 

 emphatically dclared that these dormitories and passage-ways contained no 

 Utter, refuse or nesting material, nor any remains of the otter's food, nor did 

 he discover any side-pockets or offsets, in which the animals would have 

 brought forth their young, other than those already described. 



"The following summary of the construction of this dormitory or play- 

 house seems the most reasonable that can be offered : It had originally been 

 dug (probably hundreds of years ago) from the bottom of the creek, then 

 running deep against the bluff in which it is located, and had been excavated 



