2l8 NEW RED SANDSTONE. 



band of brecciated rocks, termed by Professor Phillips the Haffield 

 Conglomerate, which is about 200 feet in thickness.^ 



Traces of Permian rocks (red and brown sandstones, with marly 

 partings, 50 feet) occur south of Ashby-de-la-Zouch, in Leicester- 

 shire ; but they form a doubtful fragmentary and unimportant 

 deposit. The Magnesian Limestone is absent. Breccias occur in 

 places, often in a gravelly and loose state, so that in one locality 

 the deposit is known as the ' Poxon gravel.' The pebbles of the 

 gravel and breccia forming the Permian deposits appear to have 

 come from the west, no trace of Charnwood rocks having being 

 discovered amongst them.^ The Poxon (or ' Small-pox ' gravel) 

 owes its name to the occurrence of numerous nodules of red 

 haematite, and these contain fossil Plants, MoUusca, etc., of the 

 Coal-measures, from which rocks the nodules have evidently been 

 derived.^ (See p. 163.) 



In Nottinghamshire the following divisions have been made : — 



Upper Marls and Sandstone 5 to 90 feet 



Upper Magnesian Limestone 20 to 40 ,, 



Middle Marls and Sandstones 20 to 140 ,, 



Lower Magnesian Limestone 25 to 60 ,, 



Marl Slates with Breccia at base 10 to 200 ,, 



The breccia or conglomerate may be the representative of the Quicksand. It is 

 a brecciated calcareous conglomerate, containing pebbles of chert, quartz, and 

 sandstone, and is known as " Plumcake." It was exposed in a cutting of the 

 Erewash Valley railway at Grives Wood. Here about 15 feet of shales intervened 

 between the Conglomerate and the Magnesian Limestone. 



At South Scarle in Lincolnshire the Marl Slates are estimated 

 to have a thickness of 200 feet, and the higher figures above given 

 are based on the thicknesses of the Permian beds proved in the 

 boring at that locality.* 



It has been suggested that the lower New Red breccias in 

 Devonshire may be of Permian age. (See sequel.) There are 

 also beds of sandstone in Alderney, and of conglomerate in Jersey, 

 which may be of Permian or of Triassic age.* 



Economic products, etc., of the Permian Beds. 



The Magnesian Limestone, geologically speaking, is one of the most changeable 

 of beds. The stone itself is usually of a yellowish colour, and crystalline 

 structure. In composition it contains nearly equal proportions of the carbonates 

 of lime and magnesia, with two or three per cent, of silica: and it is sometimes 

 termed Dolomite or Dolomitic Limestone, a name given after the 'geologist 



^ Mem. Geol. Survey, vol. ii. part i, p. iii. 



* See E. Hull, Geol. Leicestershire Coal-field, p. 57 ; Rev. W. H. Coleman, 

 Geology of Leicester, 1846 (White's History) ; and W. J. Harrison, Ibid. 1877. 



•^ W. S. Gresley, Midland Naturalist, ix. pp. i, etc. 



* E. Wilson, Midland Naturalist, iv. 122; W. T. Aveline, Geology of Notting- 

 ham, p. II. 



5 Ansted and Latham, The Channel Islands, 1S62 ; J. A. Birds, G. Mag. 

 1878, p. 79. 



