The fossil now defined exists, like whinstone and porphyry, both in masses and in veins, though most frequently in the former. It is like them unstratified in its texture, and is regarded here, as being also unstratified in its outward structure.[26] One ingredient which is essential to granite, namely, quartz, is not contained in whinstone; and this circumstance serves to distinguish these _genera_ from one another, though, in other respects, they seem to be united by a chain of insensible gradations, from the most homogeneous basaltes, to granite the most highly crystallized. [Footnote 26: Those rocks that consist of the ingredients here enumerated, if they have at the same time a schistose texture, or a disposition into layers, are properly distinguished from granite, and called Gneiss, or Granitic Schistus. But it has been questioned whether a stone does not exist composed of these ingredients, and destitute of a schistose texture, but yet divided into large beds, visible in its external form. Dr Hutton supposes such a stone not to exist, or at least not to constitute any such proportion of the mineral kingdom, as to entitle it to particular consideration, in the general speculations of geology. Whether this supposition is perfectly correct, may require to be farther considered: this, however, is certain, that a rock, in all respects conformable to it, composes a great proportion of what are usually called the granite mountains. See NOTE XV.] 78. Granite, it has been just said, exists most commonly in masses; and these masses are rarely, if ever, incumbent on any other rock: they are the basis on which others rest, and seem, for the most part, to rise up from under the ancient, or primary strata. The granite, therefore, wherever it is found, is inferior to every other rock; and as it also composes many of the greatest mountains, it has the peculiarity of being elevated the highest into the atmosphere, and sunk the deepest under the surface, of all the mineral substances with which we are acquainted. Notwithstanding the circumstance of not being alternated with stratified bodies, which constitutes a remarkable difference between granite and whinstone, the affinity of these fossils is such as to make the similarity of their origin by no means improbable. Accordingly, in Dr Hutton's theory, granite is regarded as a stone of more recent formation than the strata incumbent on it; as a substance which has been melted by heat, and which, when forced up from the mineral regions, has elevated the strata at the same time.