the trench on the north-east side; but many more measurements in other analogous cases would he requisite for a trustworthy result.
The amount of fine earth brought to the surface under the form of castings, and afterwards transported by the winds accompanied by rain, or that which flows and rolls down an inclined surface, no doubt is small in the course of a few scores of years; for otherwise all the inequalities in our pasture fields would be smoothed within a much shorter period than appears to be the case. But the amount which is thus transported in the course of thousands of years cannot fail to be considerable and deserves attention. É. de Beaumont looks at the vegetable mould which everywhere covers the land as a fixed line or zero, from which the amount of denudation may be measured.[1] He ignores the continued formation of fresh mould by the disintegration of the underlying rocks and fragments of rock; and it is curious to find how much more philosophical were the views, main-
- ↑ "Leçons de Géologie pratique, 1845; cinquième Leçon.' All Élie de Beaumont's arguments are admirably controverted by Prof. A. Geikie in bis essay in Transact. Geolog. Soc. of Glasgow, vol. iii. p. 153, 1868.
