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Show 2 IN'l'RODUCTION. im1nediately adjoins one which has long remained undisturbed for pasture, and where the vegetable mould is exposed on the sides of a ditch or hole. The subject may appear an insignificant one, but we shall see that it possesses some interest; and the maxim "de minimis lex non curat," docs not apply to science. Evon Elie do Beaumont, who generally undervalues small agencies and their accumulated effects, remarks.* "la '' couche tres-mince de la terre vegctale est un "monument d'une haute antiquite, et, par lc "fait de sa permanence, un objet digne d'oc" cuper le geologue, et capable de lui fournir "des remarques interessantes." .Although the superficial layer of vegetable mould as a whole no doubt is of the highest antiquity, yet in regard to its permanence, we shall hereafter see reason to believe that its component particles are in most cases removed at not a very slow rate, and are replaced by others due to the disintegration of the underlying materials. As I was led to keep in my study during many months worms in pots filled with earth, * 'Lcs:ons Je Geologic Pratique,' tom. i. 1845, p. 140. IN'l'RODU01'ION. 3 I became interested in them, and wished to learn how far they acted consciously, and how much mental power they displayed. I was the 1nore desirous to learn something on this head, as few observations of this kind have been made, as far as I know, on animals so low in the scale of organization and so poorly provided with sense-organs, as are earth-worms. In the year 1837, a short paper was read by me before the Geological Society of London,* ~'On the Formation of Moulu" in which it was shown that small fragmen't s of burnt marl, cinderfi, &c., which hau been t.hickly strewed over the surface of several meadows, were found after a few years lying at the depth of some inches beneath the turf but still forming a layer. This apparent' sinking of superficial bodies is due, as was first suggested to 1ne Ly Mr. Wedgwoou of Maer Hall in Staffordshire, to the large quantity of fine earth continually brought up to the surface by worn1s in the form of castings. These castings are sooner or later * ' Transactions Gcolo0 • Soc.' vol. v. p. 505. HonJ .N ovcmber 1, 1837. B 2 |