214 NEW RED SANDSTONE. 



The Permian rocks are largely developed in the north-eastern 

 and midland counties. 



In Northumberland and Durham the beds consist chiefly of 

 Magnesian Limestone underlaid by Yellow Sand and Sandstone. 

 (See p. 2 10.) The beds occur as far north as Cullercoats near 

 Tynemouth, and they are exposed in the cliffs from North and 

 South Shields, by Marsden Bay, Sunderland, Ryhope, and Seaham, 

 to East and West Hartlepool.^ 



A thickness of 50 feet has been assigned to Upper Permian Marls, 

 above the Magnesian Limestone in Durham, but in the opinion of 

 Mr. E. Wilson, it is doubtful if these beds are represented.'* The 

 Magnesian Limestone in this area is divided as follows:^ — 



f Upper Limestone Yellow, oolitic, botryoidal, concretionary, and 



crystalline limestone of Whitburn, Marsden, 

 P\il\vell, Roker, Hartlepool, etc. 250 feet. 



Middle Limestone "Shell and Cellular limestone" ("Fossiliferous 



Magnesian and Pseudo-brecciated limestone" of Prof. 



King) of Tunstall and Humbleton Hills, 

 Limestone. Ryhope, Galley's Gill, Down Hill, Clack- 



sheugh, etc. 150 feet. 



Lower Limestone "Compact Limestone" of Pallion, Whitley, 



Pensher, Houghton-le-Spring, Ferry Hill 

 south of Durham, Thickley, etc 200 feet. 



Marl Slate Marl Slate of Clacksheugh, Down Hill, Midde- 



ridge. Ferry Hill, East Thickley, near 

 Bishop Auckland, etc. 10 to 30 feet. 



The Marl Slate of Durham is noted for fine specimens of fossil 

 fishes {^Pal(Xonisais, Platysomus, etc.). Ferry Hill being a well-known 

 locality, as well as Fulwell near Sunderland. The rock is a 

 laminated shaly limestone or calcareous shale. It has also yielded 

 a few Mollusca, and some Plant-remains (^Ncuropteris, etc.). 



In Yorkshire the Permian rocks form a band extending through 

 Bedale, Masham, Ripon, Knaresborough, Wetherby, Tadcaster, 

 Pontefract, and west of Doncaster, to Tickhill and W^orksop. 



It is considered by some observers that the different members of 

 the Permian formation are not strictly conformable to one another. 

 A most decided instance of unconformity (due to contemporaneous 

 erosion) is stated to occur in the railway-cutting at Tadcaster. 

 The Middle Marl has there thinned away to a mere seam, so 

 that the Upper Limestone rests almost directly on the Lower, and 

 at the base of the former there is a thin bed of gravel formed of 

 Lower Limestone pebbles.* 



1 Observations on the red sandstones of Tynemouth, the original drifting of the 

 beds, and the direction of the old currents, have been made by Dr. H. C Sorby. 

 Geol. and Polyt. Soc. W. Riding, iii. 234. 



■- Midland Naturalist, iv. 188. 



■■ Sedgwick, T. G. S. (2), hi. 37 ; J. W. Kirkby, Q. J. xx. 345 ; Kirkby and 

 Binney, Geologist, vi. 196. See also R. Howse, Trans. Tyneside Nat. Club, 

 iii. 239 ; Ann. Nat. Hist. 1S57, xix. i. 



* Explan. of Quarter-Sheet 93 S.W. (Geol. Survey), by W. T. Aveline, A. H. 

 Green, and others. 



