Geological Society. 313 



geologist now informs us that his conjectures have been verified, 

 and that at Christcliurch, one mile beyond the superficial boundary 

 of the coal-field, the 10-yard and other seams have been reached by 

 borings carried down to the depth of nearly 300 yards. Adverting 

 to this discovery, he directs attention to the possible extension of 

 other carboniferous tracts beneath the surrounding new red sand- 

 stone of Shropshire, Worcestershire, Staffordshire, and other cen- 

 tral counties. 



It is clear that these geological considerations must be duly 

 weighed by those who speculate on the probable future duration of 

 British coal, according to the actual or any assumed rate of con- 

 sumption. 



Mr. Murchison, in describing the Dudley and Wolverhampton 

 coal-fields*, informs us that he has not yet found any fossil remains 

 of decidedly marine origin, like those observed by Mr. Prestwich 

 in Coalbrook Dale. The shells seem to be all of fresh-water ge- 

 nera, and the Megalichthys Hibherti, and other fish occurring at 

 Dudley, of species identical with those of the coal measures of Edin- 

 burgh, may have inhabited fresh water. 



The same author has coloured on an Ordnance Map the super- 

 ficial area oi the Silurian rocks connected with the coal-fields above 

 mentioned, and has shown that the Lickey quartz rock between 

 Bromsgrove and Birmingham, of which the geological position has 

 remained hitherto uncertain, is in fact nothing more than altered 

 Caradoc sandstone, a member of the lower Silurian group. The 

 same appears as a fossiliferous sandstone in one district, while in 

 another it passes into a pure quartz rock, a modification attributed 

 to the proximity of underlying trap, for analogous changes have 

 been seen at neighbouring points where the absolute contact uf the 

 sandstone with the trap is visible. 



We are also indebted to Mr. Murchison for some interesting 

 remarks on the dislocations of the strata in the neighbourhood of 

 Dudley, and particularly for a description of some dome-shaped 

 masses, from the centre of which the beds have a quaquaversal dip. 

 He speculates on the probable dependence of these phaenomena 

 upon the protrusion of volcanic matter from below, at points where 

 it has been unable to find issue. It would, I think, have been more 

 satisfactory, if, in confirmation of his theory, some natural section of 

 one of these dome-shaped masses could be pointed out, where not 

 only a nucleus of trap was apparent, but could be shown to have 

 taken up its actual position in a soft or fluid state. Even if we 

 should find in some instances a subjacent central mass of trap, por- 

 phyry or granite, not sending out veins or altering the strata, the 

 folding of the beds round such a protuberance might admit of an 

 explanation like that suggested by Dr. Fitton. He has supposed 

 a set of yielding horizontal strata to be pressed upon by a sub- 



*[ The abstract of Mr. Murchison's memoir on these coal-fields appeared 

 in Lond. and I'Minb. Phil. Mag., vol. ix. p. 489. — Edit.] 



Third SerUs, Vol. 10. No. 6\, April 1837. 2 S 



