ON THE FORMATION OF CRYSTALLINE ROCKS. 231 



which up to that time had been little else than an assemblage of 

 •conjectures.* 



To go back to the doctrines which were in vogue at the time when 

 the idea of metamorphism appeared, we ought first to call to mind the 

 fundamental principles of the celebrated professor of Freyberg, es- 

 pecially those which have disappeared in the progress of subsequent 

 discoveries. According to "Werner, granite and the other crystalline 

 rocks are marine deposits, as much so as the stratified and fossilifer- 

 ous rocks. At a remote period the different materials from which the 

 strata were derived were either dissolved or held in solution in the 

 ocean. It was from 'this chaotic ocean that all the strata were, one 

 after the other, precipitated, some by chemical and others by me- 

 chanical means. This later mode of formation distinguished the 

 crystalline from the sedimentary rocks. According to this system, 

 granite, which composes the highest peaks of the globe, and which 

 also supports the regularly stratified deposits, was formed first, to- 

 gether with gneiss and the crystalline schistose rocks which are as- 

 sociated with it. As no organic remains are ever found in them, the 

 formation of these deposits necessarily preceded the existence of ani- 

 mals and vegetables, whence they received the name of primitive ; af- 

 terward the sea became shallower, and sank away into the interior 

 cavities of the earth.f During this second period a chemical precipi- 

 tation of the silicates continued to take place, but at the same time 

 mechanical deposits began to be formed. By this double process, at 

 once chemical and mechanical, the intermediate or deposits of transi- 

 tion which contain crystalline associated with sedimentary fossilifer- 

 ous rocks were formed. During a new period of the decrease of the 

 waters the secondary strata were deposited, the highest mountains of 

 which, it was then thought, never reached the altitude of the peaks 

 of the older deposits. They are often in horizontal beds and abound 

 in organic remains. During their consolidation, the strata expe- 

 rienced ruptures from which resulted cavities of all dimensions. 

 The water, in leaving these cavities, incrusted the long fissures, 

 through Avhich it flowed, with the different materials it held in solu- 

 tion, and thus gave rise to metallic veins. Such, according to Wer- 

 ner, is the origin of all the strata composing the crust of the globe, 

 not including, however, the alluviums, the vegetable earth, and the 

 products of volcanic fire, which he attributed to the conflagrations of 

 the beds of carbonaceous combustibles. He explained the intimate 

 relation which evidently exists between the primitive and secondary 

 deposits, both in their mineralogical relations and in their association, 

 by supposing that the composition of the ocean, and consequently 

 the nature of its deposits, have varied from the time when granite 

 was precipitated from it, sometimes by a gradual and sometimes by a 



-By the aid of positive facts, wliich Fiichsel had previously, in part, described in 1762, 

 Werner proved that a kind of chronology of the physical events which had contributed to 

 the formation of the globe could be established 



fLeibnitz had already tried to explain the drying up of continents by the retreat of the 

 water into vast interior voids, whicJi he attributed to ancient cavities of gaseous inflation 

 produced at the time of the primitive fusion. 



