THE NORTH-EAST OF ENGLAND. 537 



to the details of this process I hope on a future occasion to be able 

 to give more definite results*. 



One word as regards the origin of the lower breccia. This 

 striking rock band (the miners' " mingled " or " plumcake " rock) 

 maiutains its average thickness and coarse texture over a consider- 

 able area, and mnst have been simultaneously deposited over several 

 square miles, and in water of variable depth and distance from land. 

 Though no striae have, I believe, been found, the angularity and con- 

 fused arrangement of the fragments, the fact that some of the largest 

 have travelled a long distance, the general absence of any attempt at 

 stratification, and the sudden transitions in thickness and texture of 

 the breccia, point possibly to its glacial origin, as droppings, say, from 

 the melting of icebergs or ice-floes. (Occurring, however, along a 

 plane of erosion, no such special theory may seem required to account 

 for its origin.) The same remarks may apply almost equally well to 

 the uppermost or Lower Bunter breccia. 



To Richard Johnson, Esq., Engineer to the Great Northern Rail- 

 way Company, the author desires to express his acknowledgments. 

 The principal section exhibited is founded on the Company's sec- 

 tions he has so liberally supplied ; and its completion is due to the 

 facilities given by him for exploring the railway-cuttings from 

 their commencement to their present advanced state. 



* It will be noticed that along the line of section we have no representative 

 of the Kothliegende. This is only one of many instances in which I have met 

 with proofs of the non-existence of any such formation in Notts or Derbyshire. 

 My limited experience of the so-called' Lower Red Sandstone of Durham inclines 

 me to concur with those who would relegate such rocks to the Carboniferous 

 formation, as has been recently done with similar strata in Yorkshire. Hence 

 it appears that the Marl Slate, or in its absence the Lower Magnesian Lime- 

 stone, forms the true base of the Permian series in the north-east of England. 



