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T. V. HOLMES ON" THE PERMIAN, TRIASSIC, AND 



22. The Permian, Triassic, and Liassic Rocks of the Carlisle Basin. 

 By T. V. Holmes, Esq., F.G.S. (Read February 23, 1881.) 



[Plate XL] 



I am enabled, by permission of Prof. A. C. Ramsay, Director- General 

 of the Geological Survey, to lay before you the general results of 

 the Survey examination of the Permian, Triassic, and Liassic rocks 

 in the country bordering the Solway Firth ; but I do not propose 

 to discuss here the glacial drift and other superficial beds by which, 

 the surface of the ground is almost entirely covered, and which are 

 the main hindrance to an understanding of the rocks whicb form 

 my subject this evening. 



Papers on the Permian and Triassic rocks of the North-west of 

 England have been read before this Society by Prof. Sedgwick, by 

 Sir Roderick Murchison and Prof. Harkness, and by Mr. E. "W. 

 Binney. But as few districts promise less, except as regards drift 

 and peat-mosses, than that immediately around the Solway, it has 

 hitherto been dealt with, as awhole, in a brief and cursory fashion. 

 In addition, a knowledge of certain borings, the results of which are 

 by no means generally known, is absolutely necessary to a correct 

 view of the structure of the Carlisle basin (see Map, PI. XL). 



The lowest bed with which we are here concerned is the great 

 brick-red Upper Permian sandstone, so well shown at St.-Bees 

 Head, and named, therefore, the St.-Bees Sandstone. Between 

 St.-Bees Head and Maryport the coast consists of the underlying 

 Coal-measures, the St.-Bees Sandstone having been swept away by 

 marine denudation." But at Maryport it again becomes visible, its 

 most northerly appearance being below Swarthy Hill, on the fore- 

 shore, about midway between Maryport and Allonby. North of 

 Swarthy Hill none but superficial beds are exposed on the southern 

 shore of the Solway. On the Scottish side St.-Bees Sandstone appears 

 at Tordoff Point ; but, with this exception, a walk along the coast 

 between the Sark and the Mth shows no more than one between 

 Allonby and Rockcliff, on the southern side. At a distance of one, 

 two, or three miles from the coast-line, however, Scotland has de- 

 cidedly the advantage, the corresponding part of Cumberland being 

 entirely destitute of sections. 



Turning eastward from Maryport, the St.-Bees Sandstone is found 

 to occupy a belt of country ranging towards Dalston on the Caldew 

 and Wetheral on the Eden. Between Maryport and the Caldew 

 its southern boundary consists of Carboniferous rocks of various 

 ages : and between the Caldew and the Eden of Lower Permian 

 beds. The Carboniferous-Permian boundary is almost invariably a 

 faulted one ; in Shalk Beck, however, the unconformity between 

 the two formations is very distinctly shown about a mile above 

 East Curthwaite. The boundary between the St.-Bees Sandstone 

 and the Lower Permian beds, between the Caldew and the Eden, 



