Where the granite was little decomposed, the quartz was not easily disengaged from the mass it was imbedded in, and often broke in pieces before it could be extricated. The crystallization of the quartz, therefore, would not have been discovered, but for the decomposition of the feltspar; and it is probable, that similar crystallizations exist in many granites where they are not perceived. 292. Some mineralogists are inclined to think, that the regular crystallization of quartz is to be found only in what they call secondary granites, or in those that are of a formation subsequent to the great masses which constitute the granite mountains. It is indeed true, that in the instances given here, both from Cornwall and Daouria, the granites containing quartz crystals are from veins that intersect the primary schistus, and are therefore, on every hypothesis, of a formation subsequent to that schistus. But it does not follow from thence, that they are less ancient than the great masses of unstratified granite; with these last they are most probably coëval, nor can there be any reason for thinking the crystallization of quartz a mark of more recent formation than that of feltspar. 3. _Stratification of Granite._ 293. What are the various modes in which granite exists, is a question not absolutely decided among mineralogists. 1. That it exists as a schistose stone of a fissile texture, in gneiss and _veined granite_, is on all hands admitted, though in this state the name of granite is generally withheld from it. 2. That it exists often without any indication of a fissile texture, and altogether unstratified, is likewise acknowledged. 3. That it is found in veins, intersecting the strata, has been shown above. The only mode of its existence subject to dispute, is that in which it is said to be stratified in its outward configuration, but not schistose in its texture. On this point mineralogists do not perfectly agree: Dr Hutton did not think that this was a state in which granite ever appears. When not schistose in its structure, he supposed it to be unstratified altogether; and he considered it as a body which, like whinstone, was originally in a state of igneous fusion, and, in that condition, injected among the strata. The school of Werner, on the other hand, maintain, that granite, if not always, is generally stratified, and disposed in beds, sometimes horizontal, though more frequently vertical, or highly inclined.