Excerpt from Excelsior, Vol. 4: Helps to Progress in Religion, Science, and Literature We must then commence by telling him that the ordi nary rocks which he sees used for building-stones, for paving the streets, &c., or those which he meets with in clifl's or quarries, or of which he sees the rolled and rounded fragments in gravel-pits, were all formed in one of two ways. They have either cooled from a molten condition, the result of intense heat, or they have been deposited and compacted together under water. They are called, there fore, Igneous rocks and Aqueous rocks: The latter are often called Sedimentary, as being the result of the deposi tion of sediment in water; and Stratified, because they have been strewed out so as to form wide sheets, or beds, or strata. The igneous rocks, on the other hand, are often called the Unstratified rocks. 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.