THE POPULAR SCIENCE MONTHLY.
question to that as to species. It is not necessarily each time a different people, but sometimes the same, at first using a more simple and then a more complex implement. All mankind have not progressed equally. Some are in the Stone age now. There have been arrests in development, and a comparison of the points which the different races have reached will show the differences in standing between them. In Europe, Lyell has given a very complete account of the different kinds of implements found in one locality, the valley of the Somme. In the peat-bogs on either side of the river are found Roman weapons, belonging to the age of metals. In the gravel and clay-beds below, polished and rough stone implements are found. In North America the iron tools are wanting. The Indian was in the Stone age at the advent of Europeans. The Mound-builders had used copper, but the process of smelting and the use of iron had not been reached by them.
In the accompanying diagram, while I have indicated the geological succession of the implements of man, you must bear in mind that, since stone implements are yet used in some parts of the world, they are there found in surface or alluvial deposits. But for our race the Stone age has passed, and, to find in Europe the implements our forefathers used, we must go in most cases into lower than surface-beds. And Dr. Abbott has drawn attention to the fact that there is a great similarity between the North American and European rough-stone implements. This does not indicate so much identity of
- ↑ The difficulty of supposing man to have been originally introduced into North America during the Quaternary lies in the fact that he was most probably in the Paleolithic age when the migration was made. This difficulty vanishes, if, as I suppose, man entered upon possession of this continent during the Pliocene, before the Ice period had interfered with a passage from the north by land. This will leave us free to consider the American civilizations indigenous.