Rev. A. Irving — On the Permian and Trias. 159 



this is strong, and much stronger in Germany than in Britain. In 

 the former country there is a definitely marked system below the 

 Trias, commonly known as Dijas, from the fact that it is made up of 

 two well-defined "formations." The late Sir Roderick I. Murchison 

 was mainly instrumental in separating the lower members from the 

 upper of the series formerly known as the "New Red Sandstone"; 

 but his application to the former of the term " Permian " was 

 scarcely felicitous. He would have done better to have taken the 

 Dyassic system of Germany as a type, instead of the Russian series, 

 for these reasons : — 1. They are more sharply defined ; 2. They have 

 had an amount of labour bestowed upon them beyond all comparison 

 greater than that which has been bestowed upon the Russian series. 

 Murchison's method of pi'ocedure was arbitrary, and has been pro- 

 ductive of much confusion. I say this from conviction, and not 

 from any lack of reverence for the memory of so great a master. 

 He made a hasty, and necessarily imperfect, inspection (it could 

 hardly be called a " survey") of a series of strata which occupies 

 fully one-half of the Russian European territory ; he then took upon 

 himself to apply his conclusions, drawn from what he observed in 

 the Russian series, to correct (as he thought) the Dyassic classifica- 

 tion of German geologists, on grounds, the value of which we shall 

 have to look into presently ; and having constructed, according to his 

 own notion, a " Palceozoic Trias " in place of the established Dyassic 

 system, he proceeded to apply this to the English strata, and to 

 construct, entirely (so far as I can see) on d priori grounds, a tripar- 

 tite Permian System for the British Area. 



Now, in a discussion some time ago at the Geological Society of 

 London,^ 1 find Professor T. McKenny Hughes maintaining that many 

 of the so-called Permians were only " stained Carboniferous ; that the 

 fossil lists had been founded on a wrong classification, which had not 

 yet been set right ; that the Permian system must be broken up, 

 and part given back to the Lower New Red and Magnesian Lime- 

 stone system previously so well established, and part to the Carbon- 

 iferous." Mr. J. J. Harris Teall, M.A., F.G.S., expressed to me 

 his opinion that the description of the Permian series of Russia, 

 contained in Murchison's Geology of Russia and the Ural Mountains, 

 points to what Sir A. Ramsay calls "continental" conditions, and is 

 directly applicable to our Permian and Triassic systems taken as a 

 whole. The same gentleman urges strongly the view that rocks 

 deposited conformably upon, and in contiguity with. Coal-measures in 

 this country ought not to be called Permian ; and that any classifi- 

 cation which has the effect of obscuring the marked break between 

 the Carboniferous and the Poikilitic (Permian and Trias) systems is 

 unnatural, and should therefore be given up. 



The space in geological time which this great series of strata in- 

 tervening between the Carboniferous and Jurassic systems represents 

 is enormous. Mere adding together of the maxima of the deposits 

 gives only a rough approximation ; so many circumstances which 

 affect the rate of denudation, and therefore of deposition, have to be 

 1 Vide Quart. Journ. Geol. Soc. toI. xxx. 



