An attempt was made by M. Morlot in Switzerland to obtain the chronology of the Glacial period by studying the deltas of the streams descending the glaciated valleys. He paid special attention to that of the Tinière, a stream which flows into Lake Geneva near Villeneuve. The modern delta of this stream consists of gravel and sand deposited in the shape of a flattened cone, and investigations upon it were facilitated by a long railroad cutting through it. "Three layers of vegetable soil, each of which must at one time have formed the surface of the cone, have been cut through at different depths."[EN] In the upper stratum Roman tiles and a coin were found; in the second stratum, unvarnished pottery and implements of bronze; while in the lower stratum, at a depth of nineteen feet from the surface, a human skull was found, to which Morlot assigned an age of from 5,000 to 7,000 years. [Footnote EN: Lyell's Antiquity of Man, p. 28.] But Dr. Andrews, after carefully revising the data, felt confident that the time required for the whole deposit of this lower delta was not more than 5,000 years, and that the oldest human remains in it, which were about half way from between the base and the surface of the cone, were probably not more than 3,000 years old. Still, the significance of this estimate principally arises from the relation of the modern delta to older deltas connected with the Glacial period. Above this modern delta, formed by the river in its present proportions, there is another, more ancient, about ten times as large, whose accumulation doubtless took place upon the final retreat of the ice from Lake Geneva. No remains of man have been found in this, but it doubtless corresponds in age with the high-level gravels in the valley of the Somme, in which the remains of man and the mammoth, together with other extinct animals, have been found. We do not see, however, that any very definite calculation can be made concerning the time required for its deposition. Lyell was inclined to consider it ten times as old as the modern delta, simply upon the ground of its being ten times as large. On Morlot's estimate of the age of the modern delta, therefore, the retreat of the ice whose melting torrents deposited the upper delta would be fixed at 100,000 years ago, and upon Dr. Andrews's calculation, at about 20,000. But it is evident that the problem is not one of simple multiplication. The floods of water which accompanied the melting back of the ice from the upper portions of this valley must have been immensely larger than those of the present streams, and their transporting power immensely greater still. Hence we do not see that any conclusions can be drawn from the deltas of the Tinière to give countenance to extreme views concerning the date of the close of the Glacial period.[EO] [Footnote EO: Lyell's Antiquity of Man, p. 321.]