PART II. CHAPTER XII. 



153 



Neptunian Theory Hutton on Granite. 



the name ofJfMz, or flat ; and every deposit more modern than 

 the chalk, or uppermost of the flotz series, was designated " the 

 overflowed land," an expression which may be regarded as 

 equivalent to alluvium. As the followers of Werner soon dis- 

 covered that the inclined position of the " transition beds," and 

 the horizontality of the flotz, or newer fossiliferous strata, were 

 mere local accidents, they soon abandoned the term flotz ; and 

 the four divisions of the Wernerian school were then named pri- 

 mitive, transition, secondary, and alluvium. 



As to the trappean rocks, although their igneous origin had 

 been already demonstrated by Arduino, Fortis, Faujas, and 

 others, and especially by Desmarest, they were all regarded by 

 Werner as aqueous, and as mere subordinate members of the 

 secondary formations.* 



This theory of Werner's was called the " Neptunian," and for 

 many years enjoyed much popularity. It assumed that the 

 globe had been at first invested by an universal chaotic ocean, 

 holding the materials of all rocks in solution. From the waters 

 of this ocean, granite, gneiss, and other crystalline formations, 

 were first precipitated ; and afl;erwards, when the waters were 

 purged of these ingredients, and more nearly resembled those of 

 our actual seas, the transition strata were deposited. These were 

 of a mixed character, not purely chemical, because the waves 

 and currents had already begun to wear down solid land, and 

 to give rise to pebbles, sand, and mud ; nor entirely without fos- 

 sils, because a few of the first marine animals had begun to ex- 

 ist. After this period, the secondary formations were accumu- 

 lated in waters resembling those of the present ocean, except at 

 certain intervals, when, from causes wholly unexplained, a par- 

 tial recurrence of the "chaotic fluid" took place, during which 

 various trap rocks, some highly crystalline, were formed. This 

 arbitrary hypothesis rejected all intervention of igneous agency, 

 volcanos being regarded as partial and superficial accidents, of 

 trifling account among the great causes which have modified the 

 external structure of the globe. 



Meanwhile Hutton, a contemporary of Werner, began to teach, 

 in Scotland, that granite as well as trap was of igneous origin, 

 and had at various periods intruded itself in a fluid state into dif- 

 ferent parts of the earth's crust. He recognized and faithfully 

 described many of the phenomena of granitic veins, and the al- 

 terations produced by them on the invaded strata, which have 

 been treated of in the ninth chapter. He, moreover, advanced 

 the opinion, that the crystalline strata called primitive had not 



* See Principles of Geology, vol. i. cliap. iv. 



