362 Mr. Smith's Discoveries in Geology. [May, 



not being accidentally or capriciously distributed therein, but 

 that each particular species of these organic remains (when such 

 species are with the requisite accuracy discriminated) has its 

 proper and invariable place in some particular stratum or bed 

 of the successive laminae of the earth, and having then drawn 

 the conclusion, and verified it by an extended research, that 

 some one, or an assemblage of two or more of these species of 

 fossil shells, &c. may serve as new and more distinctive marks of 

 the identity of most of the strata in England * than were pre- 

 viously known or resorted to by mineralogists or others. 



9. Having ascertained by the actual tracing and examining of 

 great lengths of most of the upper and middle strata of England, 

 that the mineralogical characters, as well as the more obvious or 

 useful qualities of nearly all of them, vary so considerably in 

 different parts of their course and breadth of surface as to render 

 any names for such strata, or descriptions of them, founded on 

 mere mineral characters, very uncertain and useless ; f yet, 

 probably, no instance has occurred of any remarkable or useful 

 quality of, or property attending a stratum (including its nodules 

 and organized fossils) having occurred in one place only, but 

 more commonly such occur in numerous places on its range ; 

 nearly all the properties of a stratum more or less often and 

 suddenly appearing to decrease, and, perhaps, to disappear 

 locally, to increase again to perfection, and after a greater or less 

 length of range or breadth, again to decrease and disappear, and 

 so on. 



10. Having ascertained that although the strata of nearly all 

 the south-east and east of England have a general and easy dip 

 towards the south-east, it is not as one flat plane that they so 

 dip or decline, but they are waved in a somewhat parallel manner, 

 almost like the surface of a ploughed field ; and on the great 

 scale are found to form ridges and troughs -X 



11. Having by the collection of very numerous specimens 

 actually ascertained the particular species of fossil shells and 

 other organic remains, which distinguish ten or more of the 

 principal strata of England ; having observed that often where 

 extraneous alluvium is absent the organic remains of the strata 

 show themselves in the ploughed soil ; and having extensively 

 used these in conjunction with the other new means above 

 mentioned, of tracing and identifying the strata previous to 1799 ; 

 and having in that year made and circulated several manuscript 

 copies of a list of such shells, &c.§ occupying a series of 23 of 



• On Aug. 5, 1807, Mr. Farej published an explicit notification of these disco- 

 veries and conclusions by Mr. Smith, as to fossil shells, in the latter part of the 

 article Coal, in Dr. Rers's Cyclopedia. 



t Derbyshire Report, vol. i. 



+ Phil.'Mag. for April, 1812, vol. xxxix. p. 271, note. 



k The Rev. Benjamin Richardson, of Farley ; William James, Esq. of Wels- 

 bourn ; and the late Rev. Joseph Townsend, of Pewsey, were among those who 

 at first received copies of (he list here spoken of, which was drawn up at Mr. 



