OEIGIN OP CRYSTALLINE ROCKS. S 



In the system of Hutton, however, a wide distinction is made between the two rocks. 

 Grueiss was no longer a primitive or original rock, as taught by Lehman and by Werner, 

 bnt, like the other crystalline schists, designated by Hutton as Primary, was supposed to be 

 " formed of materials deposited at the bottom of the sea, and collected from the waste of 

 rocks still more ancient." In his system " water is first employed to arrange, and then fire 

 to consolidate, mineralize, and lastly to elevate the strata ; but with respect to the unstra- 

 tified or crystallized substances the action of fire alone is recognized." " Hutton also con- 

 ceived the pressure of the waters of a superincumbent ocean to exert an important influ- 

 ence in the consolidation of the sediments. He is thus a plutonist only so far as regards 

 granite and other tinstratified rocks, while in maintaining a detrital origin for the crystal- 

 line schists he, as Naumann has remarked, may be regarded as the author of the so-called 

 metamorphic hypothesis of their origin. Playfair himself declares of Huttou's system : 

 " We are to consider this theory as hardly less distinguished from the hypothesis of the 

 vulcanists, in the usual sense of this appellation, than it is from that of the neptunists or 

 disciples of Werner." ' 



§ 10. It was no part of Hutton's plan to discuss the origin of those more ancient rocks, 

 which had, according to him, furnished by their disintegration materials for the primary 

 stratified rocks. It was, in the language of Playfair, a system " where nothing is to be seen 

 beyond the continuation of the present order." " His object was not . . . like that 

 of most other theorists to explain the first origin of things." This system, as interpreted 

 by his school, asserts the conversion of detrital rocks into masses indistinguishable from 

 those of truly igneous origin, which were the sources of the first detritus. The changes 

 which it assumed to be wrought by the alternate action of water and fire on the earth's 

 crust were not supposed to be limited by any external conditions in the nature of things, 

 and were compared by Playlair to the self-limited perturbations in the movements of the 

 heavenly bodies, in which, as in the geological changes of the earth's crust, " we discern 

 no mark either of the commencement or termination of the present order." 



§ 11. Hutton's system is th^^s concisely resumed by Daubrée : — " The atmosphere is the 

 region in which the rocks decay ; their ruins acciimulate in the ocean, and are there mine- 

 ralized and transformed, under the double influence of pressure and the internal heat, into 

 crystalline rocks having the aspect of the older ones. These re-formed rocks are subse- 

 cjuently uplifted by the same internal heat, and destroyed in their turn. The disintegration 

 of one part of the globe thus serves constantly for the reconstruction of other i)arts, and the 

 continued absorption of the underlying deposits produces incessantly new molten rocks, 

 which may be injected among the overlying sediments. We have thus a system of 

 destruction and renovation of which we can discern neither the beginning nor the end." ** 



§ 12. It was this perpetual round of geological changes, which took no account either of 

 a beginning or an end, that led the theologians of his day to oppose the system of Hutton. 

 On the other hand, in the system of Werner, which taught the fashioning of the present 

 order of our globe from a primeval chaos beneath the waters of a universal ocean, they saw 

 a conformity with the Hebrew cosmogony which recommended to them the neptunian 



* Playfair, Illustrations, etc., pp. 12 and 131. 



' Biographj' of Hutton ; Playfair's Works, vol. iv., p. 52. 



* Daubrée, Études et Expériences, etc., p. 12. 



