Br. Wheelton Hind — Correlation of Carboniferous Boclcs. 507 



been delayed for so long ; but however useful from the numerous 

 facts it contains, I must take exception to the deductions made from 

 them. The pajoer is a remarkable one, because, while having for its 

 object the correlation of rocks which occur over a wide expanse of 

 country, no appeal has been made to palgeontological evidence to 

 clinch the author's views which are based on purely stratigraphical 

 considerations. 



The paper would have been so much more helpful, too, if 

 Mr. Gunn had carried his table of correlations farther south, and 

 given his opinion as to the equivalents of the beds shown in his 

 scheme to a typical section of the Carboniferous sequence in Derby- 

 shire ; for no correlation of Carboniferous rocks can be satisfactorily 

 established without a consideration of the important Carboniferous 

 sequence of the Midlands. 



Mr. Gunn's hj'pothesis, briefly stated, is, that the Lower Scottish 

 Limestones of the East of Scotland do not represent any part of the 

 Mountain Limestone of Yorkshire, but are the equivalent of the 

 upper part of the Yoredale Series of Phillips, and that the lower 

 part of the Yoredale Series of Phillips and the Great Scar Lime- 

 stone of Yorkshire are represented in Scotland by the Calciferous 

 Sandstone Series. 



Now it is an important fact that the fauna of the Mountain Lime- 

 stone of Derbyshire and Yorkshire is identical with that of the whole 

 of the Yoredale Series of Phillips and the Great Scar Limestone, and 

 further, that the fauna of the Limestones of the East and West of 

 Scotland is also characterized by the presence of the majority of the 

 same forms ; while, on the other hand, the fauna of the Calciferous 

 Sandstone Series is very different indeed, containing only very few 

 species, which go up into the Carboniferous Limestone Series. 



I have attempted to show these palgeontological results in a paper 

 in the Geological Magazine of February, 1898, and have based 

 a table on them for the correlation of the British Carboniferous 

 rocks, which is very different from that now given by Mr. Gunn ; 

 and I believe the recognition that the Yoredale Series of Phillips is 

 nothing more than the upper part of the Carboniferous Limestone of 

 Yorkshire and Derbyshire, which has been split up by wedges of 

 shale and sandstone coming in fi'om the north, to be the key of the 

 problem, a view which the identity of the faunas proves to be almost 

 certain. 



A mere consideration of the thickness of the various series of 

 strata tends to the same conclusion. What has happened that 

 the mass of limestone in South Yorkshire is from 2.000 to 

 8,000 feet thick, while at Ingleborough, a distance of about 

 20 miles, its supposed representative, the Great Scar Limestone, is 

 only 500 feet thick? What, again, are the representatives in 

 Lower Wharfdale of the 1,000 feet of Yoredale beds in Weusleydale 

 with seven thick beds of limestone? 



My contention that the Carboniferous Limestone splits up as it 

 passes north, forming moi'e and more beds of limestones on its way, 

 some of which, however, do not extend as far as others, is splendidly 



