278 Rev. IV. D. Comjbeare on a Geological Map of [April, 



Pontefract rock ; and this first grit rock, I doubt not it would 

 appear to be which my friend has represented as surrounding 

 westwardly the trough of lower coal measures on the west of 

 Masham ; "but which rock mistakenly has been coloured as a 

 continuation from Swill Hill, mentioned p. 275, of his " flag- 

 stone rock," answering to my fourth grit. 



Similar remarks apply to the smaller coal trough on the west 

 of Patrick Brompton, although its strata are in part covered and 

 superficially bounded on the east, by unconformable upper red 

 marl, overlapping previously the yellow limestones and their 

 intervening gypseous marl, and then the edge of the Pontefract 

 rock, in these parts. 



I will now only further remark, that the cause of the disap- 

 pointments seems now apparent, from the boreings made some 

 years ago in search of coals on the west of East Rigton village, 

 south of the Wharfe River, and westward of Sicklin Hall and 

 Spoftbrth, on the north of the river, as well as those older trials 

 doubtless made, but, perhaps, not recorded, in the Collingham 

 denudation, mentioned p. 275, viz. that no thick or valuable 

 seams of coal occur, in so loiv a part of the carboniferous series ; 

 but which spots, even yet, it would seem, my friend considers 

 to have strata higher in the series than the fourth grit rock, the 

 usual limit downwards, in these parts, of marketable seams. 



I 5.m, Sir, yours, &c. 



John Farey. 



Article VIII. 



Memoir illustrative of a general Geological Map of the principal 

 Mountain Chains of Europe. By the Rev. W. D. Conybeare, 

 FRS.&c. 



{Continued from p. 218.) 



* # * In citing the authority of Boue as confirming the opinions 

 of Prof. Buckland and myself, with regard to the distinction 

 between the todteliegende and old red sandstone of England, I 

 was not aware that he had formerly entertained different views ; 

 this I have since learned from his memoir on Germany, inserted 

 in the volume of the Wernerian Transactions recently published. 

 That memoir, however, was read in the beginning of 1822, 

 before the appearance of the arguments on this subject brought 

 forward in the " Outlines." Since that period, M. Bouc has 

 enjoyed opportunities of studying many other localities of this 

 formation, and has, with a candour that does him honour, made 

 the concession which I have quoted ; the letter I have cited 

 bears date Vienna, Jan. 14, 1823. It maybe considered, there- 



