344 W. Gunn — Carboniferous Rocks of England ^ Scotland. 



below the Melmerby Scar Limestone, so it is evident that the 

 floor on which the Carboniferous rocks were deposited was a very- 

 uneven one. 



The section in Weardale is very similar to that in Teesdale, except 

 that the Lower Carboniferous rocks are not reached. 



When we reach Northumberland we find that the Mountain 

 Limestone of Ingleborough is divided by intercalations of sandstone 

 and shale so as to resemble in character the Yoredale Series above. 

 This was long ago pointed out by Phillips, who says : — " The 

 principal changes, as we proceed northward, appear to happen in 

 the lower part of the limestone group, which loses its individuality, 

 by admitting between its beds a constantly increasing quantity of 

 mechanical admixtures, and at length becomes a subordinate feature 

 in a country which has the characters of a coalfield." ^ As we 

 proceed from South to Mid-Northumberland, while the upper or 

 Yoredale Limestones are generally persistent, the lower limestones 

 representing the Great Scar gradually become thinner and less 

 important, and in many cases disappear entirelj^, so that eventually 

 we find that nearly all the important limestones are in the upper or 

 Yoredale Series. The work of my colleagues on the Geological 

 Survey, as given in the published maps, is the authority for this part 

 of Northumberland. 



For Mid-Nortlmmberland reference may be made to the admirable 

 memoir by the late Mr. Hugh Miller on " The Geology of the Country 

 around Ottei-burn and Elsdon " (1887), in which the announcement 

 was made (see p. 5) of the identity of the Eedesdale Limestone 

 with the Dun Limestone of North Northumberland. Mr. Miller 

 and myself had many conferences on the correlation of the Lower 

 Carboniferous rocks, and he entirely concurred in the main results 

 embodied in this paper. In this district the next limestone above 

 the Eedesdale is called the Fourlaws, and both these limestones 

 traced into South Northumberland are found to lie far below the 

 true Yoredale Limestones, and they therefore are portions of the 

 Great Scar. 



The North Northumberland section, somewhat generalized, is 

 represented in the third column where the Drj-burn Limestone is the 

 uppermost of the Yoredales. Coals occur throughout the series down 

 to the Fell Sandstones, but are omitted generally for the sake of 

 clearness. It will be seen that the principal limestones fall into 

 two natural groups, in the upper of which the limestones are 

 numerous and pretty frequent (down to the Oxford), while several 

 hundred feet lower come the Woodend and the Dun Limestones. 

 Below these is the group containing the Scremerston Coals, 800 

 to 900 feet thick, in which also limestones occur, but they are always 

 thin (from 1 to 4 feet each), and are for the most part plant-limestones 

 of an estuarine or fresh-water character. Underlying the coals 

 is a thick sandstone group — the Fell Sandstones — and at the bottom 

 of the section is a portion of the Lower Carboniferous group called 



1 Manual of Geology, p. 165 (1855). 



