Excerpt from Useful Knowledge, or a Familiar Account of the Various Productions of Nature, Mineral, Vegetable, and Animal, Which Are Chiefly Employed for the Use of Man, Vol. 1 of 3: Illustrated With Numerous Figures, and Intended as a Work Both of Instruction and Reference; Minerals The first layer is frequently a rich, black mould, formed almost wholly of animal and vegetable remains. This yields sustenance to the vegetable productions; and thereby becomes the actual, though not the imme diate, support of the whole animal creation. - Beneath this is Often found a thick bed of clay, that furnishes to man a substance of which to make bricks, tiles, various kinds of pottery, and innumerable other articles for the comfort of social life - Next are deposited vast beds of gravel, that are of use in numerous points of view. Underneath this are the infinitely varying strata of sand-1 stone, limestone, &c. Which not only serve for the con struction of buildings, and for other important purposes, but also frequently surround mines which contain the valuable metals.-beneath a slaty stratum are usually discovered those immense beds of coal so requisite for the comfort, and, in some situations, even for the exist ence of man. These strata, it is true, are not always found together, nor are they always discovered in the same Order; but the statement will suffice to show the general nature of their arrangement. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.