26o THE POPULAR SCIENCE MONTHLY. 



been seen, but, like many similar deposits in Europe and America, had 

 been looked upon as natural beds of sea-sliells deposited in past times, 

 and after their formation elevated by upheaval. It was not until Steen- 

 strup, of Copenhagen, first took up the critical study of similar deposits 

 along the shoi'es of the Baltic, and showed that the deposits were really 

 the work of man, and of ancient man, that attention was attracted to 

 these beds in other parts of the world. 



Thanks to several years' study of these deposits along the coast of 

 New England, in company with Prof. Jeffries Wyman, I was enabled to 

 recognize the character of the Omori deposit at once. The railway passes 

 directly through it, and most of it has been removed for ballasting the 

 road. The bed evidently covered the field beyond the track for a consid- 

 erable distance, judging from the quantity of shells and fi'agments of pot- 

 tery which were strewed in the adjacent rice-field. The deposit varied 

 from a few inches to two feet and a half in thickness, and the layer of 

 earth above varied from two feet to nearly five feet in thickness. This 

 great depth of soil above the shells might have been brought in by man, 

 as the Japanese are famous for the manner in which they level the ground 

 and fill in depressions. The thickness of soil above a deposit is always 

 an untrustworthy guide in estimating the age of such a deposit : as, 

 for example, the deposits about Salem, Massachusetts, containing pre- 

 cisely the same kinds of pottery and bone-implements, and presumably 

 of the same age, will have in one place a thickness of two feet of soil 

 above, and in the sterile pastures a thin layer of a few inches. The 

 Omori deposit is made up of shells which still live in the bay of Yeddo, 

 though I have not yet been able to study the living forms sufficiently 

 to ascertain whether any changes have taken place in the fauna since the 

 heaps were made. A number of genera are found, representing, among 

 others, Ehurna^ Turbo, Ceritheimi Area, Peeten cardiwn, two species of 

 Ostrea, and, curiously enough, large valves of the common clam, J/ya are- 

 naria, hardly to be distinguished from the same species so common along 

 the New England coast. The position of the Omori heap is striking. 

 The shell-heaps of New England, Florida, and nearly all places where 

 they have been observed, are always in immediate proximity to the shore 

 or river. In some places, as at Goose Island, Maine, the ocean encroaches 

 upon the deposits and is gradually removing them. Rev. James Fowler, 

 in commenting upon the absence of shell-heaps along the New Bruns- 

 wick coast, offers this as one of the evidences that the sea is encroaching 

 upon the land, and calls attention to the fact that buildings, which stood 

 at some distance from the shore fifty years ago, have since been washed 

 away.* Along the shores of the Baltic, the shell-heaps, on the contrary, 

 are a mile or more from the shore, and this fact, with evidences of a ge- 

 ological character, shows a practical encroachment of the land upon the 

 sea by upheaval since the deposits were made. 



The Omori deposits, like those of the Baltic, are some distance from 



' " Smithsonian Annual Report " for 18Y0, p. 389. 



