72 



That it did increase very largely, there is hardly any room to doubt. To 

 show this, the increased number of shell-heaps of this period is sufficient. 



They extend over all the islands, the Peninsnla of Aliaska, and we 

 have in the National Museum bone implements of pattern similar to those of 

 the Mammalian layer, obtained near the mouth of the Stakhin or Stikine 

 River. These last are dissimilar to Indian weapons, and the modern 

 Indians of that region never use bone for arrow-points. I am tolerably 

 well satisfied that the deposit whence these were obtained is also an Innuit 

 shell-heap. Where we have made excavations we have found the Mamma- 

 lian layer varying from two or three feet to eight or ten feet in thickness. 

 The combined thickness of the shell-heaps (including the deposits of the 

 Fishing and Hunting Periods), on Iliuliuk Spit, Unalashka, is about fifteen 

 feet. The difference is chiefly due to the differences in population and 

 length of occupation of the various localities. We have no means of esti- 

 mating the length of time required to produce these accumulations, but we 

 may obtain hints of it from the facts relating to the Amaknak Cave. Here 

 we have the three skeletons deposited some time during the Fishing Period. 

 These were then gradually covered by an accumulation of mold, resulting 

 from the decay of vegetable matters and organic refuse, possibly brought 

 in by foxes who might have had their nests in the cave, or partly from 

 material which might have gradually worked its way in from the exterior 

 by the aid of the weather. This would have been a very slow process, 

 when we note that the cave is so protected by its contracted aperture that 

 hardly anything could be carried in by the wind; the bottom not being 

 below the natural surface of the outer soil, it would receive little or no 

 wash from the flat outside. Considering the great antipathy, exhibited by 

 the Innuit generall}^, to approaching a burial-place of this kind, to say 

 nothing of camping on it, the covering of the remains buried there nnist 

 have been complete, and the original use forgotten, before the deposition of 

 the next layer could have been commenced. The Cave Rock, as shown in 

 the sketch, stands on a narrow isthmus, and, being a damp place, presents 

 no qualifications for a dwelling. The layer C is composed of kitchen 

 refuse, bones, broken arrow-heads, odds and ends of carvings half finished, 

 &c., &c. It seems evident to me that it was made by occasional jjarties of 



