298 Mr. MuRCHisoN on the Coal-field of Brora in Sutherlandshire, 



near the gorge^ through which the river flows^ and the shaft is sunk to the 

 depth of 230 feet*. An account of the beds cut through in 1811 is annexed 

 in the Appendix,, but unfortunately the fossil remains were not at that period 

 scientifically distinguished. One of these beds only is now exposed to view 

 on the sides of the shafts and is a compact calcareous ironstone, very similar 

 to that which is so largely distributed throughout the coal-formation of the 

 Scarborough coast. The first beds which are open to examination, form the 

 roof of the coal, and are about 2 feet 7 inches in thickness : the upper part is 

 an aggregate of fossil shells, cemented together with calcareous matter and 

 quartzose grains : the lower part is made up of a compressed assemblage of 

 leaves and stems of plants, crossing each other, and passing into shaly coal. 



The broken and decomposing shells are mixed with carbonaceous matter, 

 grains of quartzose sandstone, much pyrites, some crystals of sulphate of iron 

 and selenite. I refer to the tabular view (p. 318.) for a detail of all the fossil 

 shells ; remarking that this bed alone has afforded 24 different species, of 

 which 16 are well-known fossils of the oolitic series of England: amongst 

 the hitherto undescribed shells, Mr. J. Sowerby has upon this occasion named 

 and figured two species of the new genus pholadomya, one ammonite, one 

 cardium, and one sanguinolaria. (Min. Con. tab. 545, 546, 548, 549.) 



Many of the fossils of this bed are analogous to those of the pier stone near 

 Scarborough, which there overlies the main coal-seams: the Gervilliag, trigo- 

 niae, univalves and ostreae of these two beds, so far removed from each other, 

 are identical; and perhaps the most remarkable feature in this coincidence is, 

 that a bivalve not yet figured, (which Mr. Sowerby is inclined to refer to the 

 new genus Pullastra,) is most abundant at Brora, and likewise characterizes 

 all the strata above the coal on the N. E. coast of Yorkshire. 



I am indebted to my friend Mr. Konig for the following account of the 

 plant from the roof of the Brora coal, which he has identified with one of the 

 fossil vegetables collected by me on the Yorkshire coastf , 



'' The vegetable remains in sandstone, slate-clay and clay-ironstone from the 



* The section of a shaft, subsequently sunk at the engine pit 780 yards distant from the above, 

 is also placed in the Appendix. This account as revised by Mr. Bald, was given by that gentle, 

 man in the Memoirs of the Wcrneriau Society. By comparing these two sections, it will be seen 

 that the beds vary much less than might have been expected, when the distance between the shafts 

 is considered. 



t This plant has been figured in a work containing much valuable detail, viz. Messrs. Young 

 and Bird's " Survey of the Yorkshire Coast :" but its botanical characters neverhaving been scien- 

 tifically given, I avail myself of Mr. Konig's description, and have annexed drawings of it, as seen 

 ill the sandstone of Yorkshire and the coal. shale of Brora. (See Plate XXXII, ) 



