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the Carboniferous and Permian formations, we must never forget 

 that we know nothing whatever of the dislocations affecting the 

 disposition of the Carboniferous beds north of the faulted boundary 

 line. For the superficial beds prevent us from seeing anything 

 of most of those which affect the Permian, Trias and Lias ; while 

 faults of the utmost magnitude may affect the Carboniferous 

 series below, yet not extend into the Permian and other formations 

 above. While, if we may judge of the faults likely to exist in the 

 Carboniferous rocks north of the Carboniferous-Permian boundary 

 from those south of it, we may consider them likely to be both 

 numerous and important. And no help can be derived from 

 observation of the Carboniferous rocks on the Scottish side of the 

 Border, inasmuch as they are divided from those of the area under 

 consideration either by a broad belt of Permian-covered ground, or 

 by the waters of the Solway. 



In addition to the unconformity between the Carboniferous and 

 the Permian formations, we must not omit to consider that in the 

 Coal-Measures themselves — the unconformity between the White- 

 haven Sandstone and the beds on which it rests. This of course 

 implies that the base of the Whitehaven Sandstone may be on very 

 different horizons at different places, and that coals existing below 

 it at one spot may have been denuded away during its deposition 

 at another. The peculiar rock, mainly purple-grey in colour, 

 known as the Whitehaven Sandstone, is well shown in the cliffs 

 between the harbour at Whitehaven and St. Bees Head ; and the 

 unconformity between it and the underlying measures is visible to 

 any careful observer, and has been long recognised by geologists. 

 I do not think the magnitude and practical importance of this 

 unconformity in any way comparable to that between the Carbon- 

 iferous and the Permian formations, and consequently would deal 

 with it very briefly but for one circumstance. Mr. J. D. Kendall, 

 in the valuable paper read by him last year on " The Structure of 

 the Cumberland Coal Field,"* includes in the term " Whitehaven 

 Sandstone" not only the rock visible at Whitehaven, Rose Gill, 

 and other places, which has long been considered to belong to it, 



* Proc. N. Eng. Inst. Mitt. Eng., Vol. xxxii. p. 319 (1883). 

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