344 



coasts of Cumberland and Lancashire," by the Rev. A. Sedgwick, 

 F.G.S. F.R.S., Woodwardian Professor in the University of Cam- 

 bridge, &c. 



The author states that this paper is a continuation of two former 

 communications, and that the details, now laid before the Society, 

 define the geographical limits of the central Cumbrian Mountains ; 

 a general description of which will form his next object. 



§ 1. He first traces the geographical distribution of the new red 

 sandstone series, which commencing near Kirkby Stephen is ex- 

 panded, between the central Cumbrian chain and the carboniferous 

 chain of Cross Fell, to the Solway Firth. He then traces the mem- 

 bers of the same series along the north-western coasts of Cumber- 

 land and Low-Furness ; pointing out their modifications of structure 

 — the analogies they present to other British formations of the same 

 age — and their i-elations to the older rocks on which they rest. 



The author describes some protruding masses of the carboni- 

 ferous series within the area of the new red sandstone. Of these 

 he enumerates three examples: — 1st. A contorted mass of car- 

 boniferous limestone in the plateau of Broadfield, about five miles 

 south of Carlisle. — 2ndly. A mass of yellow magnesian limestone 

 at Chalk Beck to the east of the village of Rosley. From its fossils, 

 structure and position, he concludes that it is an outlying mass of 

 the carboniferous limestone. — 3rdly. Some masses of carboniferous 

 limestone, sandstone and shale near Aketon, about three miles north 

 of Wigton : and he states his belief that in no place within the area 

 of the red sandstone, could a search for the small beds of coal which 

 alternate with the limestone be made with a greater probability of 

 success than near this place. 



§ 2. He then describes in detail the successive deposits exhibited 

 in a coast section extending from the cliffs north of Whitehaven 

 to St. Bee's Head. They are enumerated in the ascending order as 

 follows : — 



(1.) Great carboniferous system of Whitehaven ; of which some 

 of the great faults and dislocations are briefly noticed. 



(2.) A coarse sandstone of great thickness, generally with a red- 

 dish tinge, containing, though rarely, traces of calamites, and some- 

 times appearing to graduate into the true coal measures. It is, how- 

 ever, shown to be on the whole unconformable to the carboniferous 

 series, and to be the exact equivalent of the " lower red sandstone," 

 described in a former paper (Geol. Trans, vol. iii. part I. p. 6h), 

 which separates the magnesian limestone and conglomerates from 

 the Yorkshire and Durham coal-fields. It is further compared with 

 a red sandstone, which in Shropshire separates the true coal mea- 

 sures from the magnesian, porphyritic conglomerates. 



(3.) Magnesian conglomerates, sometimes ofconsiderable thickness, 

 and formed in the hollows and irregularities of the "lower red sand- 

 stone" (No. 2.). They are identified with the similar conglomerates 

 of the valley of the Eden, and of various parts of Yorkshire and of 

 Shropshire ; and they appear to be on the exact parallel of the 

 similar conglomerates of the Mendip Hills, Exeter, and the south- 

 western coal-fields. 



