1048 Remarks on the Geology, $c. \_Dec 



nesia, sometimes as much as 35 or 40 per cent.* Moreover in a practi- 

 cal point of view, it is of the greatest consequence to distinguish these 

 two rocks, as coal never occurs associated with the magnesian lime- 

 stone, properly so called. In the same work the author talks about 

 the discovery of shell limestone in the coal formation ; no doubt 

 he discovered limestone with shells, which frequently abound in 

 the coal limestone ; the other term however is strictly applied to a 

 rock which is much newer and of rare occurrence, which has not 

 as yet been met with in England. Murchison, however, has stated, 

 that he has found its equivalent on the European continent; it occu- 

 pies a position between the red marl, and the new red sandstone. It 

 is the Muchelkalk of the Germans. To distinguish therefore between 

 these, and at the same time to apply their proper names, is of conse- 

 quence, which can be easily done by examining the fossil proper 

 to each ; characteristic of the latter, we have Encrinilis, Monitiformis, 

 Avicula, Socialis, and Ammonites, Nodasus, &c, and of the former 

 Producta Serebralulse, or the Ceratitis, &c. 



There is another circumstance worthy of notice here, viz. Red 

 Sandstone. It is not to be supposed that when sandstone is of a red 

 colour, it must always belong either to the old or the new red sand- 

 stone, an erroneous idea which has led to many errors, and much 

 censure by foreign geologists. To find red sandstone alternating with 

 the white sandstone of the coal measures (a fact which ought to be 

 recollected by individuals engaged in searching for coal in this coun- 

 try,) in Europe, is not unfrequent. In lower Silisia nearly the whole 

 of the coal field is composed of reddish brown, and cochineal co- 

 loured sandstone, with which great beds of coal alternate.t In Scot- 

 land, in the Lothians, alternations of the red and white sandstone 

 in the coal fields are frequently met with. J This rock (red sand- 

 stone) seems to occur in great abundance in this country ; its relations, 

 however, have not been properly investigated. In a report drawn 

 up for the Coal Committee by Dr. M'Clelland, there is much in- 

 teresting information in regard to it ; of the rocks which enter into 

 the composition of the coal formation, we have already mentioned as 

 occurring among the Himmalehs sandstone, slate clay, bituminous 

 shale, and limestone. To make the series complete, we want, fine 



* Edinburgh New Phil. Journal. Analysis of Limestone from the neighbourhood of 



Trap Dumifrieshre, by William Copland, Esq. In the same Journal many 



similar analyses will be found, 



f Notes to the Geology of Dumfrieshire, by Professor Jameson. 



t Ibid. Locis Citatis and Cunningham's Essay on the Geol. of the Trans. 



vol. VII, 



