374 ARTIFICIAL SHELL-DEPOSITS IN NEW JERSEY. 
near Rome, know what great results may proceed from insignificant causes where the cumu- 
lative power of time has been at work, so that a hill may be formed out of the broken pot- 
tery rejected by the population of a large city. To them it will appear unnecessary to infer, 
as some antiquaries have done, from the magnitude of these Indian mounds, that they must 
have been thrown up by the sea. In refutation of such an hypothesis, we have the fact that 
flint arrow-heads, stone axes, and fragments of Indian pottery have been detected through- 
out the mass.’’ * 
The same author noticed shell-deposits on the coasts of Massachusetts. 
During his voyage round the world Mr. Darwin saw shell-heaps in the 
island of Terra del Fuego. He says: 
‘‘The inhabitants, living chiefly upon shell-fish, are obliged constantly to change their 
place of residence; but they return at intervals to the same spots, as is evident from the 
piles of old shells, which must often amount to many tons in weight. These heaps can be 
distinguished at a long distance by the bright green color of certain plants which invariably 
grow on them.” t 
We may expect to meet with artificial shell-accumulations, or at least traces 
of them, almost in all parts of the American coasts where an aboriginal popt- 
lation existed, and they have already been found in various places besides 
those mentioned, as for instance in Newfoundland and in California, and we 
shall doubtless hear of further discoveries as soon as proper attention is paid 
to these memorials of the native inhabitants of the American continent. 
The occurrence of the Danish refuse-heaps, whose age is lost In the dawn 
of history, and of similar comparatively recent deposits in America, shows 
that the conditions of existence of those Baltic islanders and the American 
coast inhabitants were essentially the same, and furnishes a striking illustra- 
tion of the similarity in the development of man in both hemispheres. A 
thorough investigation of the American shell-mounds will not only enable us 
to compare them more minutely with the corresponding remains of Europe, 
but may, possibly, disclose important facts relative to the former condition of 
the American race, and thus enlarge our stock of ethnological knowledge. 
* A Second Visit to the United States of America, by Sir Charles Lyell, (New York, 1849, ) 
vol. i, p. 252. 
t Journal of Researches, &c., by Charles Darwin, (New York, 1846,) vol. i, p. 272. 
