443 



astonishing power, in Derbyshire, Staffordshire, and other adjacent coun- 

 ties, as to give the opportunity of examining the out-crop, or appear- 

 ance on the surface, of these strata, which were originally covered by all 

 the strata which have been enumerated above. The last discovered, en- 

 trochaj, limestone of Derbyshire, must have originally lain, according to 

 Mr. Farcy's calculation, three miles perpendicularly lower than the upper 

 part of the chalk strata. 



Previously to considering more particularly the superior strata, it is 

 necessary to make a few remarks on these strata of COAL and of limestone, 

 which appear originally to have existed at such considerable depths. The 

 coal measures, according to the observations of Mr. Farey, when found 

 at or near the surface, are in situations in which, by the agency of that 

 unknown power just alluded to, the strata which had lain over them has 

 been removed*. Coal, as I have already endeavoured to show, appears 

 to be the product of vegetable matter, buried under particular circum- 

 stances, as is almost proved by the simple fact of the traces of vegetables 

 being almost constantly discoverable in it and in its accompanying strata. 

 If this opinion be correct, coal may then have been formed at any period 

 since the creation of vegetables ; and of course it would be improper to 

 confine its origin, as is done in the first of these volumes, to that period 

 at which the deluge occurred which is spoken of by Moses. The ob- 

 servations of Werner support this opinion, he having ascertained the 

 formation of coal to have taken place at different periods, from that 

 formation which rests on the granite rock, and is accompanied by por- 

 phyry and greenstone, to that of bituminous wood, peat, &c. 



The ENTROCHAL LIMESTONES of Derbyshire, &c. have their antiquity 



* Similar instances of this abstraction of the superior strata which has been observed by 

 Mr. Farey, in Derbyshire, have been also discovered by Dr. Richardson, in the basaltic 

 country in the counties of Derry and Antrim. Mr. Farey denominates these exposures of 

 the inferior strata, denudations, and Dr. Richardson those removals of the superior strata, 

 abruptions. Phil, Trans. 1808. 



