1859.] HULL TIIIXXIXG-OUT OF THE SECONDARY EOCKS. 65 



and other authors for descriptions of these rocks, I proceed to make 

 some observations on the topographical distribution of the Lower 

 Permian rocks or tlothe-todte-liegcnde. 



The red and purple sandstones, marls, and brecciated conglomerates 

 of which the Lower Permian formation is composed, attain their 

 greatest development along a band of country stretching from west 

 to east, including parts of the counties of Salop, Worcester, Stafford, 

 and Warwick ; while in the north-west districts of Cheshire, where 

 the Trias has been deposited in great force, the Permian rocks are 

 but sparingly represented. 



I beg to call particular attention to this fact, because it shows how 

 great has been the break in the order of succession, in consequence 

 of considerable changes in the distribution of land and sea between 

 the Palaeozoic and Mesozoic epochs. 



From sections published by the Geological Survey, traversing the 

 Permian rocks of Enville in Salop, the thickness of the formation has 

 been found not less than 1700 feet*. On both sides of the South 

 Staffordshire Coal-field, the thickness is probably not less than this ; 

 and Mr. Howell's estimate of the maximum depth of the large mass 

 of these red rocks in the neighbourhood of Coventry is 1800 feetf. 

 The north-eastern limit of the formation appears to skirt the southern 

 edge of the Leicestershire Coal-field ; thence trending along a north- 

 west line, it crosses the centre of the Xorth Staffordshire Coal-field ; 

 from thence it may be traced at intervals north wai'd into Scotland J. 

 1 ts westerly limit is the Denbighshire Coal-field. Its southern limit 

 is not so easily defined, and this fact forms a most seiious question in 

 specidating upon the descending series of rocks which underlie the 

 districts of Oxfordshire and Northamptonshire. It would be a sub- 

 ject for small congratulation if, on sinking for coal over these districts, 

 it shoidd be found that while the Lower Mesozoic rocks had become 

 comparatively thin, the Permian formation existed in great force 

 beneath. As Mr. Godwin- Austen has truly stated, such questions, in 

 tin absence of direct experiment, can be solved only by a restoration 

 of the land-surfaces and coasts of the period ; and, we may add. by a 

 knowledge of the sources from which the sedimentary materials have 

 been derived. 



A. Distribution of Land and Sea at 0u Lower Permian Period. — 

 There is the strongest evidence for believing that there was a much 

 larger extenl of land-surface during the formation of the Permian 

 rocks than during that of the Trias. Professor Ramsay§ has 

 demonstrated with, it appears 1" me, greal probability, that the 

 breccias which occupy ;i centra] position in the Rothe-liegende of 

 Salop and Worcester are the ice-drifted debris of sub-aerial regions of 

 tin' Longmynd and adjacenl Silurian ranges. TheAlberbury breccia 



* Horizontal Sections, Sheet •"••'5. 

 t Horizontal Sections of the Geological Survey, She I 51 

 ' See Mr. Binney, " On the Permian beds of the North-west >>f England," Item. 

 Lit. & Phil. Soc Manchester, L855. Also Prof.Sedgwiok, Trans. GeoL8oc.2ser.ToLiT. 

 J Quart. Jburn, Geol. Soc. vol. \i. p. 186. 



II See • Silurian System,' p. 18 I'.', when' the anthor traces tin- origin of some of 

 the fragments of the breooia t.> certain freshwater limestones of the Coal-meai 



VOL. SYI. — PAST I. F 



