I UK TKIASSIC SYSTEM 



357 



O f two part^, (1) hard, red -brown, pebbly sandstones, 

 about 600 feet thick, and (2) hard, n-<l<li>b BOD \ithout 



pebble, about 400 feet. Eastward, by Wigan, Manchester, and 

 Stockport, they overlap the Lower Mottled sandstone*, >o as to 

 rest on the Dyassic and Carboniferou- rock-. 



On the east side of the Soiith Staffordshire coalfield the Pebble 

 Beds occupy a broad strip of country from Birmingham to the 

 river Tame north-west of Tamworth, and they recur in a narrow 

 strip along the western side of the Ashby coalfield in Leicester- 

 shire. In the same way from the borders of North Staffordshire 

 coalfield, they pass eastward to Ashbourn and Derby, lying \villi 

 complete unconformity on the edges of the Lower 1 Carboniferous 

 rucks. 



The Upper Mottled Sandstone. This resemble* the 

 Lower sandstone, but is generally of a bright red, variegated with 

 yellow and white. From Shropshire, north of Shrewsbury, its 

 outcrop runs northward by Ellesmere along the flanks of the 

 Peckforton Hills, which rise to heights of 800 and 900 feet, and 

 thence through Delainere Forest to Runcorn and Warrington on 

 the Mersey. In the Peckforton HilLs the outcrop is repeated by 

 several strike faults which have led to the formation of as many 

 nearly parallel escarpments, the western slopes of which are 

 occupied by this soft, reddish sandstone, while their summit ridges 

 consist of the hard basement conglomerate of the Keuper. 



In the southern part of the Midland area all the Bunter stages 

 thin out toward the south-east, one overlapping the other, a fact 

 which may be regarded as proof that the pre-Triassic floor sloped 

 from the south-east to the north-west The following table 

 indicates this attenuation and overlap : l 



2. North-Eastern and Northern Areas 



Having described the typical development of the Bunter Series, 

 it will suffice to indicate briefly their occurrence beyond the limits 

 of this Midland area. 



