ON MINERAL VEINS. 396 rated by infiltration. Chalcedony is produced in the latter way, quartz in both ; while the veins of quartz and of carbonat of lime, are generated in this man ner. I have also already proved that the theory of infiltration explains the imbedded nodules of the arnygdaloids ; and thus there is established a conside rable list of minerals formed by means of aqueous so lution. That which takes place in this case, may equally happen in a mineral vein. Though we have not yet proved that all the other earthy saline materials, such as gypsum and barytes, are produced from watery solution, chemistry and analogy both render it very probable; and these may therefore be added to the aqueous list, with little hazard of error ; certainly with much less than they could be referred to an igneous origin. Lastly, we may possibly also refer to the same division, those which are found associated or imbedded in quartz, as disthene is ; though such cases as this are far more questionable. The list constructed from these various kinds of evidence will therefore contain the following minerals, and possibly many more; and it is here divided under these several heads of more or less unexceptionable proof. I do not add those which are imbedded in primary limestone ; because it is more than probable, that these have undergone the process of fusion ; in which case their imbedded minerals must be referred) as those of granite are, to an igneous origin. Saline Minerals. Carbonat of Lime Float of Lime (lypsum Brown Spar Arragonite Carbonat of Barytes Sulphat of Barytes Carbonat of Strontian Sulphat of Strontian Boracite Wavellite.