G8 Sir R. I. Murchison on the inapplicability of the new 



numerous tracts the deposits of this age are frequently not divisible 

 into three parts. In Central Germany, where the Musehelkalk forms 

 the central band of the group, with its subjacent Bunter Sandstein 

 and the overlying Keuper, the name was indeed well used by Al- 

 berti, who first proposed it ; but when the same group is followed 

 to the west, the lower of the three divisions, even in Germany, is 

 seen to expand into two bands, which are laid down as separate 

 deposits on geological maps of Ludwig and other authors. In these 

 countries, therefore, the Trias of Alberta's tract has already become 

 a Tetras. In Britain it parts entirely with its central or calcareous 

 band, the Musehelkalk, and is no longer a Trias ; but, consisting 

 simply of Bunter Sandstein below, and Keuper above, it is therefore 

 a Dyas ; though here again the Geological Surveyors have divided 

 the group into four and even into five parts, as the group is laid 

 down upon the map — iSTo. 62, 'Geographical Survey of Great Britain.' 



The order of succession in the Permian group all along the western 

 side of the Pennine chain or geographical axis of England proves 

 the impossibility of applying to it the word " Dyas ;" for over wide 

 areas in Shropshire and Staffordshire it is one great red arenaceous 

 series, with a few subordinate courses of calcareous conglomerate. 

 Following it to the north, Mr. Binney has demonstrated that the 

 fossils of the Zechstein show themselves in the heart of red marls 

 which occupy on the whole a superior part of such a red series ; and 

 in tracing these rocks northwards he has demonstrated that there 

 are, besides, two great underlying masses, first of conglomerates and 

 breccias, and next of soft red sandstones, the latter attaining, as he 

 believes, a thickness of not less than 2000 feet. Here then the Per- 

 mian may be considered a Trias. Prof. Harkness, in a memoir he 

 is preparing, estimates the thickness of these Lower Sandstones and 

 Conglomerates to the IS".E. of "West Ormside, in Cumberland, at 4000 

 to 5000 feet, and shows that they are siirniounted by marl-slates 

 bearing plants, thin-bedcled red sandstone, grey shale, and sandstone 

 and limestone, the latter — the representative of the Magnesian 

 Limestone — being covered by red argillaceous shale*. Now in all 

 these cases the Permian is a series divisible into three or more 

 parts. But when we follow the same group into Scotland, it there 

 parts with its calcareous feature, and, becoming one red sandstone of 

 vast thickness, is again a Monas. 



I have entered into this explanation because my friend, Dr. Gei- 

 nitz, has seized upon one illustration in my work ' Siluria ' which 

 shows that in certain tracts, where the Zechstein or Magnesian 

 Limestone is subordinate to an enveloping series of sandstones, the 

 Permian of my classification is there as much a tripartite Palaeo- 

 zoic group as the Trias of Central Germany is a triple formation of 

 Mesozoic age. Unless, therefore, the data to which my associates and 



* The red clay or argillaceous shale which covers the limestone is sur- 

 mounted at Hilton, in Cumberland, by five hundred feet of red sandstone, -which, 

 though perfectly conformable to the subjacent Permian rocks, he considers to 

 belong to the Bunter Sandstein of the Trias. Here, then, as in Germany, the 

 limestone may have a red cover, and yet the Bunter Sandstein be intact. 



