204 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 21, 



all analogous to the mode of formation of peat-mosses*, this of itself 

 would form an argument against the tropical character of the car- 

 boniferous flora, for peat-moss only grows and largely increases in 

 temperate and cold climates. If these arguments hold good for coal- 

 measure plants, they are equally applicable to those of the Permian 

 period, which are much fewer in number and consist principally of 

 Ferns, Catamites, ConifercB, and a few Sea-weeds. Even if the Car- 

 boniferous period could be proved to be altogether tropical, a glacial 

 episode in Permian times would not be so remarkable, seeing that 

 the unconformity of the Permian on the Carboniferous rocks is 

 everywhere so great that there is evidently no passage or direct 

 sequence in the strata, and probably between the close of the Car- 

 boniferous and the beginning of the Permian epoch a long period 

 elapsed during which our Carboniferous rocks were upheaved above 

 the waters. 



In connexion with the nature of the ancient life of the fossiliferous 

 Permian rocks of the North and East of England, a third argument 

 remains, which has even more weight than the former two. The 

 precise relation of the midland Permian beds to the true magnesian 

 limestone series has not yet been completely demonstrated. The 

 Alberbury rocks do not belong, as has been generally supposed, to 

 the true magnesian limestone of Professor Sedgwick, but are formed 

 of a breccia on the same horizon with and strongly resembling that 

 of the Abberleys and South Staflbrdshire, except that, instead of 

 trap and sandstone, the Abberley fragments are derived from the 

 carboniferous limestone to the north-west. For various reasons I 

 believe that the true magnesian limestone series is higher in the 

 Permian scale than the rocks of the midland counties f, but the 

 question is yet uncertain, the absolute proof being wanting. How- 

 ever this may be, why, considering the evidence adduced, might 

 there not be a glacial episode, marked by a consolidated Boulder- 

 clay, during Permian ages, just as we have had one in late Tertiary 

 times, that may be said nearly to approach our own ? If the newer 

 Crag, and all the Pleistocene beds of the South and North of England, 

 of Ireland, and Scotland, and the deposits now forming, were thrown 

 far back in time, solidified, and highly disturbed, we should cer- 

 tainly^, because of their fauna, include them all in one geological 

 epoch. Uncertain subdivisions might be based on the presence of 

 peculiar mammals, but the shells would be so nearly the same that 

 all geologists would agree in referring them to one period, and 

 possibly even Miocene beds might be included, but as a lower stage. 

 Yet in the midst of this period, and indeed since our existing shells 

 appeared, we have had in these latitudes a rigid arctic climate, with 

 its glaciers, its great moraines, and floating bergs, scattering detritus 

 from the Welsh, Irish, and Highland hills. The thickness of rocks 

 aflbrds no safe test of the time occupied in their accumulation, but 

 sometimes it aids in the rude estimate, and, compared even to the 



* See also Lyell's ' Elements,' 1851, p. 335. 

 t See ' Silurian System.' 



