ON PRIBILOF ISLANDS. 271 



I. Not only upon, but immediately to the rear of, the area at present 

 occupied by the breeding seals occur fragments of basalt whose angles 

 have been rounded and polished by the flippers of seals. Among these 

 latter rocks grass is found growing to an extent proportionate to their 

 distances from the present breeding grounds, and further the soil shows 

 no recent disturbance by the seals. This rounding of the bowlders of 

 the abandoned areas was not due to the impingement of sand grass 

 driven by the wind. No geologist would be willing to risk Ids reputa- 

 tion by asserting that this rounding came from any such agency. The 

 distinction between the result of sand-blast action and seals' flippers 

 is very marked. 



II. A careful examination among the roots of the grass will often 

 show the former presence of seal by Hie peculiar appearance of the soil, 

 due to the excrementa of the seal and the occurrence of a thin mat of 

 seal hair. The attention of Dr. George M. Dawson was called to such 

 a felt of hair upon the summit of Hutchinson Hill, and both he and 

 Dr. 0. Hart Merriam collected specimens of it from among the grass 

 roots at that locality. 



III. At the rear of the rookeries there is usually an area of mixed 

 vegetation — an area the boundary of which is sharply defined, and be- 

 tween which and the present breeding grounds occurs a zone of grass 

 of only a single variety. In the immediate vicinity of the present breed- 

 ing grounds only scanty bunches are to be seen. These gradually 

 coalesce as the line of mixed vegetation is approached. The explana- 

 tion of this is that the seals were formerly so abundant as to destroy 

 the normal mixed vegetation at the rear of the breeding grounds, and 

 that the decrease of the seals has been followed by the encroachment 

 of the uniform variety of grass. 



IV. The statements made to me by competent observers who have 

 lived upon the islands for years all agree that the shrinkage in the 

 breeding area has been rapid during the past live or six years. 



After observing the habits of seals for a season, I unhesitatingly 

 assert that to satisfactorily account for the disturbance to vegetable 

 life over areas whose extent is visible even to the most careless and 

 prejudiced of observers would require the presence of from two to three 

 times the amount of seal lite which is now to be found upon the islands. 



That there has been enormous decrease in the seals there can be no 

 question. 



Have observed carefully the areas occupied by the seals on the rook- 

 eries and hauling-out grounds, especially at North- 

 east Point and the reef on St. Paul Island, in 1884, johnC. Ca)itwell,pA07. 

 1885, 1S8G, and 1891, and on both rookeries the 



areas formerly occupied by seals have greatly decreased, so much so 

 that at first appearance, it seemed, in 1891, as if the hauling-out grounds 

 had been entirely deserted. Subsequent examination disclosed the fact 

 that this was not strictly true, there still being a small number of male 

 seals left on those grounds. Have also observed that the seals are 

 much more scattered on the breeding rookeries than in former years 

 (1881, 1S85, 1880); also that the number of seals in the water has pro- 

 portionately decreased, and that they have grown very much more shy 

 and difficult to approach. Without presuming to be absolutely cor- 

 rect, would estimate the number of seals present at St. Paul Island 

 during the year 1 891 to about 10 per cent of the number there in former 

 years of observation (1881, 1885, and 1886). 



