Our previous examination of the pebble had prepared us for these results; but the microscope, that mighty talisman of wisdom, has shown us, that even those infinitesimal creatures to whom a drop of water is an unbounded ocean--those living atoms of that world of being which is for ever concealed from the uninstructed mind--the inhabitants of that universe beneath us, which the eye of science can alone penetrate, existed in ages incalculably remote, and were, like their gigantic contemporaries, the living instruments by which a large proportion of the solid materials of the surface of our planet was elaborated; their imperishable siliceous and calcareous skeletons, constituting no inconsiderable amount of the crust of the earth.[S] [S] See _"Thoughts on Animalcules, or a Glimpse of the Invisible World revealed by the Microscope_," by the Author. Published by Mr. Murray, London, 1846. Fossil animalcules and corals similar to those we have discovered in the pebble and in the chalk, and hundreds of other genera and species equally minute, occur in such prodigious numbers, as to warrant the conclusion, that this class of animal existence has contributed more largely than any other, to the formation of the sedimentary strata. Not only the Chalk hills, but whole mountain-ranges formed of other deposits of great thickness and extent, are found to consist almost entirely of similar remains. In the state of rock, of sand, of clay, of marl--in the coarsest limestone, and in the purest crystal, the petrified skeletons of animalcules alike abound. The town of Richmond, in Virginia, is built on a bed of stone twenty feet thick, which is wholly composed of the fossil skeletons of different kinds of marine animalcules. The polishing slate of Bilin, in Germany, is wholly made up of the siliceous shields of similar beings, disposed in layers without any connecting medium; and these belong to species so minute, and are so closely compressed together, that in a cubic inch of the stone, weighing but two hundred and twenty grains, there are the remains of _forty-one thousand millions_ of animalcules![T] [T] See '_Medals of Creation_,' p. 221. [Illustration: Lign. 18:--Animalcules from the Richmond earth: very highly magnified[U]] [U] Note X. _Richmond Infusorial earth._ * * * * * [Sidenote: REFLECTIONS.]