1857.] during the Permian Epoch. 419 



occurs in the Bogmine outlier, and low in the Wenlock or Denbigh- 

 shire grits.* Other instances of the same kind might be cited. An 

 undescribed species of Pleurotomaria has been found at the Bog- 

 mine, and nowhere else. These facts show that the assemblage of 

 fossils in the inland and geographically higher part of the beach is 

 more exclusively of an Upper Silurian type than the assemblage 

 grouped in the geographically lower part of the same bed. Strati- 

 graphically the bed was quite continuous, and yet its opposite ends are 

 of somewhat different geological date. This point, though not 

 essential to, is intimately connected with, the proofs of a period of 

 cold during the deposition of the Permian conglomeratic breccias 

 or Rothliegendes, seeing that some of these higher Silurian fossils 

 are contained in the fragments that enter into their composition, 

 and it is therefore particularly insisted on. 



How long the island of the Longmynd remained buried beneath 

 several thousand feet of Upper Silurian rocks and old red sandstone 

 is uncertain. It is, however, certain, that this covering was partly 

 removed by denudation before the deposition of the upper coal 

 measures, for in Shropshire, part of these rocks lie directly on the 

 Cambrian strata, although Cambrian pebbles have not yet been 

 detected in them. But in the Permian brecciated conglomerates 

 of Worcestershire, many fragments, believed to be derived from 

 the Longmynd and its neighbourhood, have been found. These 

 breccias occur either themselves resting unconformably on the 

 coal measures, or on older rocks, or else associated with Permian 

 marles and sandstones that occupy like positions. These are found 

 near Enville, at Wars Hill, and Stagbury Hill, where they lie on 

 the coal measures ; at Woodbury, one of the Abberley Hills, where 

 they rest on the Upper Silurian rocks ; on Barrow Hill, on the coal 

 measures and old red sandstone ; at Howler's Heath, in the South 

 Malvern region, on the Upper Silurian strata ; and on the Clent and 

 Lickey Hills, Frankley Beeches, and at Northfield the Permian 

 rocks below the breccia rest on the South Staffordshire coalfield. 

 They also occur at Church Hill, ^\ miles north-west of the Abber- 

 ley Hills, where an outlier of breccia lies directly on the Coal mea- 

 sures of the Forest of Wyre. In all these places the brecciated 

 stones are bedded in a hardened red marly paste. The stones 

 which it contains are (with very rare exceptions) not formed from 

 tlie waste of the neighbouring rocks on which they lie, but of frag- 

 ments, many of them identical in composition and character with 

 the Cambrian and Silurian beds of the Longmynd, and consist of 

 pieces of quartz rock, greenstone, felspathic trap, felspathic ash, 

 black slate, jasper, grey and purple sandstone, green sandy slate, 

 ribboned altered slate, quartz conglomerate, and Pentamerus con- 

 glomerate and limestone. These are mixed with other foreign frag- 

 ments ; but those enumerated, always form by far the majority. 



* Named on the authority of Mr. Salter. 



2g2 



