ARTIFICIAL SHELL-DEPOSITS. 257 



Upon this echinus-layer follows one composed of fish-bones, intermixed with 

 shells of mollusks, few bird-bones, and traces of echinus-shells and spines. The 

 chief mass of this bed, however, consists of fisli-bones, compacted to such a 

 degree that bar and pick-axe were required in making excavations. It charac- 

 terizes what Mr. Dall calls the fishing-period. The thickness of this stratum 

 varies from one to three feet in different localities. The fish-remains found in it 

 (mostly heads and vertebrae) represent two kinds of salmon, the cod, halibut, 

 and several species of herrings, sculpins, and flounders. Among the artefacts 

 may be mentioned some net-sinkers in the shape of pebbles notched on opposite 

 sides. These, however, appear, according to Mr. Dall, " on the uppermost sur- 

 face of the echinus-layer, indicating that to the primitive hand-nets or scoop-nets, 

 with which the echinus-eaters might have secured their food, had been added the 

 larger, more elaborate, and more eff'ective seine."* There are mentioned, as 

 occurring in the fish-bone layer, somewhat rude knives of the kind denominated 

 " fish-knives," stone dart-heads, and, in the ujiper portion of the stratum, har- 

 poon-heads of bone. It is thought probable that skin-boats came into use during 

 this period. Mr. Dall is careful to note the progress which the presence of the 

 above-named objects implies ; yet he lays some stress on the absence of charcoal 

 in the deposit, and of those peculiar stone lamps in which fish-oil could have 

 been burned as fuel. The fish, he thinks, were eaten raw, which, to some extent, 

 still is the custom of the Aleuts. The people of this period are su^jposed to have 

 lived in huts of mats or skins, leaving no traces behind them. 



The hunting-period, finally, is represented by the uppermost or mammalian 

 layer. " The sharp line of definition between the echinus-layer and the fish-bone 

 layer, which suggested an incursion of fishermen upon the echinophagi, is not 

 paralleled in the line between this and the mammalian stratum. The distinction 

 is readily marked in an actual section of a shell-heap, but the uppermost portion 

 of the fish-bone bed contains some mammalian bones, and the mammalian bed 

 throughout, but particularly at its base, contains a fair proportion of fish-bones. 

 In fact, the change is what we might expect in the jjrogress of a race stimulated 

 by new invention or application of means which placed new, valuable, and eagerly- 

 accepted powers within their reach. "f Mr. Dall found the mammalian layer 

 varying from two or three to eight or ten feet in thickness, and the extent of 

 the deposits of this period denotes a considerable increase of thfe population. 

 " If we allow a thousand years for the duration of the littoral period, or depo- 

 sition of the echinus-layer (and I am disposed to do so), then I think that 

 fifteen hundred or two thousand years is not an excessive estimate for the dura- 

 tion of the fishing and hunting-periods. "J 



* Dall : On Succession in the Shell-Heaps of the Aleutian Islands ; p. 56. 

 t Ibid.; p. 62. 

 X Ibid.; p. 73. 



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