142 Permian Strata. 



ferous series, for while between Nottingham and the 

 neighbourhood of Leeds they lie upon Coal-measures, 

 between Leeds and the vicinity of Darlington they 

 overlap the north edge of the Yorkshire coal-field, and 

 rest directly on the Millstone Grit and associated 

 shales as far as the south end of the Durham coal-field, 

 north of which they again lie on Coal-measures. 



The limestone and marl slate are often fossili- 

 ferous. 



In Lancashire, Cheshire, and North Staffordshire, 

 the Permian strata chiefly consist of red marls and 

 sandstones, interstratified near Manchester with a few 

 thin bands of Magnesian Limestone, where both lime- 

 stones and marls are fossiliferous, containing bivalve 

 shells of the genera Pleurophorus, Bakevillia, and 

 Schizodus, Turbo, Natica, &c. Similar marls and 

 sandstones, bordered by New Ked Sandstone, stretch at 

 intervals from the border of the North Staffordshire 

 coal-field to that of Shrewsbury, and skirt the Denbigh- 

 shire coal-field on the east. In the more central parts 

 of England the same kinds of rock border the Coal- 

 brookdale, Forest of Wyre, South Staffordshire, and 

 Warwickshire coal-fields. In the Permian strata of 

 Warwickshire there are beds of conglomerate, the 

 waterworn pebbles of which largely consist of fragments 

 of Carboniferous Limestone. A few stems of trees have 

 been found in them, together with Calamites, and two 

 or three casts of shells of the genus Strophalosia 

 (fig. 31), together with a Labyrinthodont Amphibian, 

 Dasyceps Bucklandi. 



A large extent of Permian red sandstones and marls 

 occupy the beautiful Vale of Eden in Westmoreland 

 and Cumberland (see fig. 104, p. 521), from whence 

 Permian strata extend into the valleys of the Nith and 



