ORIGIN OF CRYSTALLINE ROCKS. 3 



tlie original deposition, which did not yield a regular surface, but presented elevations, 

 upon the slopes of which were subsequently laid down the Transition strata. 



Such, according to Werner, was the origin of all rock-masses except recent alluvions, 

 deposits of obviously organic origin, and the ejections of volcanoes, which he conceived to 

 be due to the subterraneous combustion of carbonaceous deposits. In the earlier ages of 

 the world there were, according to him, no volcanoes and no evidences of subterranean heat. 

 Neither in the formation of granite, of basalt, of the crystalline schists, or of mineral veins, 

 or in the displacements of the strata to be seen in the deposits of various ages, did he 

 recognize any manifestations of an internal activity of the earth.^ 



§ 5. We now pass to the consideration of the rival geological theory of Hutton, which 

 was developed at the same time with that of Werner. Saussure, as early as 1116, had 

 ascribed to aqueous infiltration the granitic veins in the Valorsine, and others near Lyons — 

 a view which was shared by Werner, who, from their similar constitution, conceived that 

 the formation of massive and stratiform granitic rocks had taken place under conditions like 

 those which gave rise to the veins in question, and then extended this view to other 

 veins and masses of what we must regard as injected or irrupted rocks, including not only 

 gi'anites but dolerites and basalts. 



Hutton and his interpreter, Playfair, on the other hand, regarded all granitic veins as 

 having been filled by injection with matter in a state of igneous fusion, repudiating the 

 notion of Salissure and of Werner that such materials could be formed by crystallization 

 from aqueous solutions. Granitic veins, according to Hutton, are in all cases but ramiii- 

 cations of great masses of granite, themselves often concealed from view. "In Hutton's 

 theory, granite is regarded of more recent formation than the strata incumbent upon it ; as 

 a substance which has been melted by heat, and which, forced up from the mineral 

 regions, has elevated the strata at the same time." ^ From this condition of igneous liquid- 

 ity, he supposed, had crystallized alike quartz and feldspar, as well as tourmaline and the 

 other minerals sometimes found in granitic veins. G-ranite is elsewhere declared by him 

 to be matter fused in the central regions of the earth. 



§ 6. With Werner, granite was the substratum underlying all other rocks simply 

 because it had been the first deposit from the chaotic watery liquid, and it was said to pass 

 into or to alternate with the distinctly stratiform or schistose crystalline rocks. In this 

 view of its geognostical relations, Werner was strictly correct, if by granite we understand 

 the massive or indistinctly stratiform aggregate which makes up what some would 

 call granite and others fundamental granitoid gneiss. This is what I have called an 

 INDIGENOUS rock, which may be with or without apparent stratification. We must, how- 

 ever, distinguish, besides this first type of crystalline rock, — the underlying granite of 

 Werner, — two others which, though mineralogically similar, and often confounded, are 

 geoguostically distinct. Of these, what I have called exotic rocks consist apparently of soft- 

 ened and displaced portions of aggregates of the first type, and are met with alike in 



' In preparing the foregoing synopsis of the views of Werner, I have followed, in part, the exposition of his 

 system given by Murray in his Review of Playfair's Illustrations of the Huttonian Theory, ijublished anonymously 

 in Edinburgh in 1802 ; in part the statements to be found in Playfair, in Bakewell, in Lyell, and in Naumann ; and 

 also the excellent analysis given by Daubrée in his Etudes et Expériences Synthétiques sur le Métamorphisme, 

 et sur la Formation des Roches Cristallines ; Paris, 1860. 



'' Playfair, Illustrations, etc., p. 89. 



