7. Though the primitive rocks occupy the lowest position _in situ_, yet they sometimes form, not only the _summits_ of lofty mountains, but sometimes the _mountain mass_ itself, and appear at the surface. In these cases it is evident that they have been _upheaved_ by a force acting beneath, and forcing them through the superincumbent rocks, which were rent, and glided down the sides of the rising mass of primitive rocks, leaving them bare and visible at the summit. In this case the rocks which were uppermost before the mountain mass began to rise, would be found at the _foot_ of the mountain; and the rocks which were next to the uppermost, would be found immediately above them, reclining on the side of the mountain; and thus _ascending through the ages of the rocks to the summit of the mountain, where we find the primitive rock formations constituting its apex_. This phenomena of primitive rocks forming the apices of mountains may be explained differently. The primitive rocks, and other classes in succession, _may have been deposited in mountain masses_, and the upper rocks being _softer_ and more _exposed_, have yielded to the ravages of the elements, and to the demolishing force of the deluge, and thus laid the primitive rocks bare. The _first_ seems to be the most probable supposition. 8. It is beyond a doubt, that in some instances, an upheaving force has operated, and elevated the granitic summits of mountains; and so powerful was the upheaving force that the blocks of granite have broke at the apex of the elevation, and some of them hang over perpendicularly in awful grandeur; and others have rolled down the sides far into the plains below. This theory of the formations of some of the principal mountains would be firmly established in every mind, if every one could have an opportunity of inspecting them without prejudice. The primitive rocks would be seen shooting up from the centre of the mountain, into lofty pyramidal elevations, resembling, sometimes, lofty spires, or cupolas; and sometimes the summit is rounded off as a dome. The rocks are in a _verticle_ position, which proves they could not have been _deposited there_ from a state of quiet repose. Sometimes two summits project from the same common base, having an intervening valley or depression between them. In this case, the rocks which lay uppermost before the mass was upheaved, upon upheaving, broke and glided down the sides, on which they depend in magnificent drapery; but the portion of them which was situated _between_ the uprising summits, not being able to escape, is found in the valley which is formed between the peaks.