Rev. A. Irving — On tJie Permian and Trias. 161 



The formations included in the Dyas are, he remarks, " two series 

 of strata sharply distinguished from each other both petrographi- 

 eally and palceontologically." This would probably have been 

 accepted as the normal order of things in Eui'ope, had it not been for 

 the way in which Murchison forced his views upon people, for 

 which he met during his lifetime with a well-merited rebuke from 

 a foreigner, M. Marcou,^ The clear and masterly description of the 

 German series, and the comparison of it with those of England, 

 Eussia, the Alps and North America, is worth any effort that may 

 be required to read what Credner has written on the subject. A 

 great deal of information may also be obtained from the two 

 writings of Murchison's to which reference has been made already : 

 they ought to be read by every student of this subject, for they 

 contain a mine of facts ; but the arguments by which these facts 

 are made subservient to foregone conclusions need analyzing. We 

 must premise here the note that the Permians of Eussia do not 

 admit of an}*- exact parallelism petrographically with the Dyas of 

 Germany ; there is no division into an upper limestone- dolomite- 

 gypsum- formation with remains of a marine fauna, such as we have 

 in the Zechstein, and a lower sandstone- conglomerate- marl-forma- 

 tion with remains of land-plants, such as is found in the Eoth- 

 liegende. On the contrary, the limestones and dolomites of the 

 Eussian series are repeated over and over again through nearly its 

 whole range ; but upon the whole the marine deposits are subordi- 

 nated to the sandstones, marls, and conglomerates. Let us now see 

 how Murchison. set to work to upset the classification adopted in 

 Germany. 



1. He points out that in some districts of Germany, and in particular 

 in the vicinity of Eisenach, where sub -atmospheric erosion has 

 carved the country into deep valleys and ravines, the hills composed 

 of Dyassic strata are capped by certain strata to which he refers 

 under the name of " Bunter-schiefer." These are comprehended in 

 the lower division of the Bunter formation by German geologists. 

 But, No, says Murchison, they form the natural capping of the hills, 

 and I claim them for the Permian, and group them with the rocks 

 on which they lie. Now this surely is not proof. The word 

 " natural " expresses only personal conviction ; and against the 

 conviction of one or two English writers on this point we have to 

 set the unanimous conviction of a host of German geologists, in 

 whose opinion the strata in question belong just as "naturally" to 

 the Bunter Sandstein, at the base of which they lie quite conformably, 

 to which also they are lithologically allied. 



2. Murchison argues from the fact that in the Permian series of 

 Eussia the marls and sandstones which overlie the uppermost dolo- 

 mite deposits contain remains of land-plants and of Protosaurians of 

 species identical with some found in Germany in the Eothliegende 

 below the Zechstein. His argument, when stripped of rhetoric, 

 comes to this : such and such remains are found in Germany below, 



^ Vide Lettres siir les Roches dii Jura, par Jules Marcou, Paris, 1860. 



DECADE II. — VOL. IX. NO. IV. .11 



