Note iii. § 7.
Primitive mountains.
148. The enumeration of the different kinds of primary schistus, at § 7, is not proposed as at all complete. It will be less defective, however, if we add to it talcose schistus, and lapis ollaris or potstone.[59]
[59] Kirwan's Mineralogy, vol. i. p. 155.
149. The rocks called here by the name of primary, were first distinguished, as forming the basis of all the great chains of mountains, and as constituting a separate division of the mineral kingdom, by J. G. Lehman, director of the Prussian mines. See his work, intituled, Essai d'une Histoire Naturelle des Couches de la Terre.[60] These rocks were regarded by Lehman as parts of the original nucleus of the globe, which had undergone no alteration, but remained now such as they were at first created; and, agreeably to this supposition, he bestowed on them, and on the mountains composed of them, the name of primitive. He remarks, nevertheless, their distribution into beds, either perpendicular to the horizon, or highly inclined, and the super-position of the secondary and horizontal strata. However mineralogists may now differ in their theories from Lehman, they must consider this distinction as a great step in the science of geology, and very material to the right arrangement of the natural history of the earth.
[60] Tom. iii. p. 239, &c. The French translation is in 1759, but the original preface is dated at Berlin, 1756.
150. Several mineralogists have agreed with him in the supposition, that these rocks are a part of the original structure of the globe, and prior to all organized matter. Of this number is Pallas;[61] and also De Luc, who applies the term primordial to the rocks in question, and considers them as neither stratified nor formed by water.[62] In his subsequent writings, however, he admits their formation from aqueous deposition, as the Neptunists do in general, but holds them to be more ancient than organized bodies.
[61] Observations sur la Formation des Montagnes.
[62] Lettres Phys. Sur l'Histoire de la Terre, tom. ii. p. 206.
151. Pini, professor of natural history at Milan, has denied the stratification of primitive mountains, in a memoir on the mineralogy of St Gothard, and in another on the revolutions of the globe.[63] His reasonings are opposed by Saussure,[64] and are certainly, in many respects, very open to attack. They proceed on a comparison between the division of rocks, by what is called the planes of their stratification, and their division by transverse fissures: two things, which he thinks so much alike, that they ought not to be referred to different causes; and, as the one cannot be regarded as the effect of aqueous deposition, so neither should the other. This is a very fallacious argument, because it confounds two things that are essentially different; and, instead of inquiring about a matter of fact, inquires about its cause. The truth is, that the dispute has arisen from not distinguishing the granite from the schistus mountains, and from involving both under the name of primitive. M. Pini seems to be in the right, when he holds the granite of St Gothard to be unstratified; but it is without any good reason, that he would extend the same conclusion to the schistus of that mountain. Charpentier, and Saussure, in his last two volumes, contend even for the stratification of granite.[65]
[63] Memoria sulle Rivoluzioni del Globo Terrestre; Memorie della Societa Italiana, tom. v. p. 222, &c.
[64] Voyages aux Alpes, tom. iv. § 1881.
[65] See Note xv. on Granite.
As the consent, if not universal, is very general for the stratification of the primary schistus, and the fact itself abundantly obvious, in almost all the instances I have ever met with, I have not considered it as necessary to enter here into any argument on this subject.