r accuracy than its author claims,
it would still only show us that from a period of from five to seven
thousand years ago, tribes of stone using folks lived in Switzerland.
It tells us nothing as to their first appearance, or the total length of
this age.<19>

Other calculations of a similar nature have been made. The Lake of
Bienne, in Switzerland, has been gradually silting up along its margins
from time immemorial. About seven hundred and fifty years ago there
was an abbey built at one place on the then existing shore of the lake.
Since that time the gain of land has been about twelve hundred feet. A
considerable distance further up the valley are found the remains of a
lake settlement of the Stone Age. If the gain of land has been uniform,
it has not been far from seven thousand years since the lake washed
round the ancient settlement. Of course the land may have gained faster
at one time than at another, but from the general configuration of the
valley it is considered that its gain was regular.<20>

Mr. Skertchly, of the Geological Survey of England, has furnished still
another estimate, based on the growth of the Fen-beds on the east
coast of England. It is sufficient to state that he also arrives at an
estimate of about seven thousand years for the Neolithic period.<21> Now
these results are interesting, and their substantial agreement is, to
say the least, striking. We must remember, however, that none of them
are free from error. They may serve to clear up our thoughts on this
subject, but we notice they tell us nothing as to the beginning of the
Neolithic Age.

Abandoning the effort to obtain dates for the various ages, attempts
have been made to calculate the entire interval that has elapsed
since the close of the Glacial times, and thus set bounds to the first
appearance of Neolithic man. We briefly touched on this question in
determining the antiquity of the Paleolithic Age, and we say, as far as
this country was concerned, it was comparatively a recent thing, but as
for Europe, it must be at a very remote time. M. Quatrefages has called
our attention to two investigations in Europe, which, in order to
understand this question, we will now glance at. The waters of the
Rhone carry into Lake Geneva every year quantities of sediment. In other
words, from this and other sources, the lake is gradually being filled
up. Carefully calculating the amount carried into the lake in a year,
estimates have been made