THE PERMIAN FORMATION. 205 



a series of shallow (a) lagoons bordering the sea. This region was 

 shut in on the west by an elevated tract of ground,the Pennine chain, (b) 

 and by a broader mass of low-lying ground, interspersed, however, 

 with hilly districts on the south. "What the eastern or northern 

 boundaries of this area were it is impossible now to say, but it is clear 

 that there must have been some sort of communication with the open 

 sea in a north-easterly direction. 



The sequence of events in this area appears to have been as 

 follows : — ■ 



Subsidence in the first place lets in the waters and inhabitants of 

 the sea. The incoming waters breaking in during a comparatively - 

 brief period of extreme shallowness and consequent violence (c) wore 

 into the carboniferous rocks forming the floor and margin of the 

 Permian basin, and out of the waste of these rocks the basement 

 breccia of the ilarl Slates of Notts and Lincolnshire was mainly built 

 up. Rivers, that took their rise on the bordering high lands on the 

 west and south, discharged their waters (and sediments) into these 

 lagoons. The streams that rose on the high ground of the Pennine 

 chain, inflowing from the west, would probably be of smaller size, and 

 carry down less but coarser sediment than those inflowing from the 

 south, the watershed being less distant, and the fall consequently 

 steeper in the case of the former. The " Quicksands " of Yorkshire, 

 which appear to he in channels cut out of the underlying carboniferous 

 rocks, and in their general structure also agree with the " rock faults " 

 met with in the coal measures, may very possibly represent, as Prof. 

 Green (d) has suggested, the deltoid deposits of such streams. Sub- 

 sidence continuing, the shales, sandstones, and dolomites that 

 constitute the Marl Slate series, were next laid down in the shallow 

 but tranquil and sheltered waters of the period. The sedimentary 

 (and chemical) constituents of these beds, were, I think, mainly washed 

 down into the Permian basin along with the remains of land plant-. 

 reptilia, and fresh-water amphibia and fishes (e) by rivers swollen 

 during periodical floods. The streams inflowing from the west, fed by 



i") The presence of ripple marks, suncracks, annelid burrows; the remains 

 of land plants, and occasionally of amphibia and reptilia in these roc 3 



irding to King, " the absence of corals and the character of the shells" prove 

 tbat they were formed in shallow water. 



fb) The Pre-Permian age of the Pennine Chain may now be considered as 

 established (Loc. cit.j 



in N.B. — It is to be understood that nothing more violent than a rapid 

 incursion of the sea over the subsiding floor of a large level-bottomed lagoon is 

 here suggested. 



On the Method of Formation of the Permian Beds of South Yorkshire," 

 by A. H. Green, M.A., F.G.S. Geol. Mag., vol. i.\. | 



"i The ganoid fishes of the Marl Slates have generically strong affinities with 

 those of the coal measure-. Prof. Miall says it is not easy to decide whether 

 the latter were marine or fresh-water, but infers, from their absence in the 

 Mountain Limestone, where Elasmobranchs abound, and their abundance in 

 the coal measures, where Elasmobranchs are almost unknown, that they were 

 mostly fresh-water, though some may have been marine, or made seasonal 

 migrations from salt-water to fresh. " Coal : Its History and Uses. The Animals 

 of the Coal Measures," pp. 135-6, 



