Vestiges of the Natural History of Creation Book

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 38 THE EARTH FORMED?ERA OF THE PRIMARY ROCKS. Although the earth has not been actually penetrated to a greater depth than three thousand feet, the nature of its substance can, in many instances, be inferred for the depth of many miles by other means of observation. We see a mountain composed of a particular substance, with strata, or beds of other rock, lying against its sloped sides; we, of course, infer that the substance of the mountain dips away under the strata which we see lying against it. Suppose that we walk away from the mountain across the. turned'up edges of the stratified rocks, and that for many miles we continue to pass over other stratified rocks, all disposed in the same way, till by and bye we come to a place where we begin to cross the opposite edges of the same beds ; after which we pass over these rocks all in reverse order, till we come to another extensive mountain composed of similar material to the first, and shelving away under the strata in the same way. We should then infer, that the stratified rocks occupied a basin formed by the rock of these twomountains, and by calculating the thickness right through these strata, could be able to say to what depth the rock of the mountain extended below. By such means, the kind of rock existing many miles below the surface caa often be inferred with considerable confidence. The interior of the globe has now been inspected in this way in many places, and a tolerably distinct notion of its general arrangements has consequently been arrived at. It appears that the basis rock of the earth, as it may be called, is of hard texture, and crystalline in its constitution. Of this rock, granite may be said to be the type, though it runs into many varieties. Over this, except in the comparatively few places where it ...