REPORT OF AMERICAN COMMISSIONERS. 339 



insr as it is believed to be. The evidence offered Undisputed de- 



crease. 



ow-ftrass 



by the physical condition of the rookeries them- 

 selves would alone be sufficient to satisfy any- 

 one that at some previous time the seal popula- 

 tion had been vastly greater than at present. 



(ll) INTRINSIC EVIDENCE AFFORDED BY THE ROOK- 

 ERIES THEMSELVES. 



Behind each rookery is a more or less sharply j,oue!"^^" 

 defined strip or belt varying from one hundred to 

 five hundred feet in width, which differs conspic- 

 uously in appearance from the ground on either 

 side. It is covered with a short and rather fine 

 grass of a yellowisli-green color (^Glyceria angus- 

 tata), more or less mixed with tufts of a coarser 

 species (Deschampsia ccespitosd), both differing 

 strikingly from the tall and rank rye grass 

 (Elymns mollis) usually growing immediately 

 behind. In many places the ground between 

 the tussocks and hummocks of grass is covered 

 with a thin layer of felting, composed of the shed 

 hairs of the seals matted down and mixed with 

 excrement, 'urine, and surface soil. This felting 

 could not have been formed otherwise than by 

 the movements of seals back and forth over the 

 ground for many years. In the same zone the 



Worn rocks. 



rough upper surfaces and angular projection of 

 the rocks -have been rounded off and polished by 



