214: Dr. Fittou's Noles on the History of English Geology. 



doctinne of formations was delivered in his lectures only, and 

 may be dated as of 1 790 or 1791; that of the transition-class not 

 until 1795 or 1796. But his theoretic views, as to the depo- 

 sition of rocks in general, and the configuration of the earth's 

 surface, — which, after all, (if what relates to the overlying for- 

 mations be excepted,) are little more than a selection from the 

 doctrmes of preceding writers, — may be collected from his 

 work on Veins, first published in November 1791; at which 

 time it is certain that he was acquainted with the works of 

 Whitehurst, for they are quoted in the book last mentioned. 



The true merit of Werner, on which it is probable his 

 reputation as a naturalist will ultimately rest, appears to con- 

 sist, in his having drawn the attention of geologists, expli- 

 citly, to the Order of succession which the various natural 

 "■roups of rocks are found in general to present ; and in having 

 himself developed that order, to a certain extent, with a de- 

 free of accuracy which before was scarcely attainable, from 

 the want of sufficient methods of discriminating minerals and 

 their compounds. He was, we believe, the first to observe, or 

 the first to diffuse the doctrine, that the masses or strata, con- 

 stituting the surface of the globe, present themselves in groups 

 or assemblages, the members of which are generally associated 

 wherever they occur, and are so connected as to exhibit a cer- 

 tain unity of character. To such assemblages Werner gave 

 the name of Formations ; and his doctrine (or hypothesis, if 

 this latter term be preferred,) was, that the exterior of the 

 earth consists of a series of these formations, laid over each 

 other in a certain determinate order. Not that the whole 

 series is anvwhere complete ; but that the relative place of its 

 members is never departed from. Thus in the ascending 

 series A, B, C, D, it may happen that B or C, or both, may 

 be occasionally wanting, and consequently D be found imme- 

 diately above A ; but the succession is never violated, nor the 

 order inverted, by the discovery of A above the formations B, 

 or C, or D, nor of B above those that follow it, &c.* 



A very important exception, however, to this regularity of 

 arrangement, is found in the position of that great class of 

 compound rocks, which includes all those of the trap family, 

 the porphyries, syenites, and some at least of the granites of 

 Werner. The compounds of this tribe, in general, agree, 

 not only in possessing the characters of crystallization, and 

 in being wholly destitute of organic remains, but in exhi- 

 biting, at their junction with the stratified substances, the 



[* The substance of this and the following paragraphs, is taken from a 

 preceding article in the Edinburgh Review, by the author of the present 

 paper; Vol. xxix. Nov. 1817, p. 71-] 



I 



