Page:Popular Science Monthly Volume 61.djvu/90

84 selenite, besides bones and teeth of the Eocene deer-like Anoplotherium, and of Dinotherium, an early forerunner of the elephant.

Upon this lower Tertiary marine bed rest the fresh water Quaternary beds, the series beginning with the lowest Pleistocene beds, passing through beds of supposed glacial origin containing transported pebbles, up into postglacial strata containing Neolithic implements.

The transition from the Tertiary formation is sudden. When the lowest Quaternary beds were deposited, the Eocene marl beds had been elevated, become dry land and exposed to the erosive action of the winds and rains. A long interval passed between the time of deposition of the Tertiary beds and the Pleistocene deposits which now cap them. It is to be observed that the later Tertiary formations (Oligocene, Miocene and Pliocene) are absent.

The Quaternary deposits at Chelles are divided into four distinct fresh water beds, each differing in age and in their materials, and as exposed by the workmen the whole series appears to be about 25 to 30 feet in thickness. They are as follows:

D, E. The lowest bed, that directly overlying the Eocene marl, consists of rolled pebbles and grayish sand, the mass being often cemented by calcareous infiltrations. This bed contains the Chellean implements. (What is apparently an upper division of this bed (D) is what the Abbé Bonno calls the Acheulean, and from it have been taken axes like those found at St. Acheul near Amiens.) In this lowest bed also occur the remains of Elephas antiquus, Rhinoceros merckii, etc.

C. A deposit, not forming a continuous bed, and only seen in places, of water worn coarse gravel and small pebbles derived from Tertiary gravels, and called by Bonno ’sables moyens.’ This is the red drift, ’diluvium rouge,’ of Ameghino. It abounds in rolled, broken, sometimes entire, Tertiary marine shells which have been brought by freshwater streams probably from Lizy-sur-Ourcq and from Etrépilly a few miles to the northeastward, or perhaps from Soissons to the north (Bonno).

B. A second layer of drift or rolled and transported gravel, containing flint implements of the Moustierian epoch, and bones of the mammoth.

A. A thin bed of gray clay of the age of the Swiss Lake-dwellers, in which occur polished stone axes.

The chief center of interest is of course the lowest bed (D, E), that containing the worked flints. These are the celebrated Chellean axes, which are of various sizes, no two exactly alike, which were worked out by chipping from flint nodules, the flint being derived from the chalk deposits. These crude weapons were probably used in the chase or in battle, and were not mounted, but held in the hand. Almond-shaped, in the form of a 'coup de poing,' they were worked on both sides or