494 Rev. A. Irving — Triassic Deposits of the Aljjs. 



tlie favour to consult my paper " On the Evidence of a Ridge of 

 Lower Carboniferous rocks under the Plain of Cheshire," ^ he 

 will see how I explain the differences in the mineral characters of 

 the lower division as it occurs ia the Midland Counties, and in the 

 Northern. 



Dublin, 18th Sept. 1882. 



IV. — Notes on the Post-Cakboniferous (Dtassic) and Triassic 



Deposits of the Alps. 



By tlie Eev. A. Irving, B.A., B.Sc, F.G.S. ; 



of "Welliagton College. 



THE purpose of this communication is to supplement the author's 

 paper on the "' Classification of the European Eocks known as 

 Permian and Trias," which has appeared in recent numbers of this 

 Magazine. It is based on a short communication made to Section C. 

 of the British Association at the recent meeting at Southampton, and 

 has been expanded into the present paper at the request of the 

 President of the Section, E. Etheridge, Esq., F.R.S. 



Eeasons were given in the former paper for not considering the 

 names ' Dyas ' and ' Permian ' as altogether suitable as general terms 

 applicable to the European area as a whole, since they severally 

 connote the respective fades of the rocks of this age in particular 

 areas. It is with geological history as with an imperfectly known 

 coinitry, one feels the desirability of great and distinctive land- 

 marks ; and such a land-mark is furnished for later Paleeozoic times 

 by the great Carboniferous system. The name ' Post-Carboniferous ' 

 was therefore proposed as a general term, and this name is here 

 retained, until a better one is proposed, upon the high authority 

 (among others) of Prof. Giimbel of Vienna as well as of that of 

 Credner. It has been urged against the use of this term, that it 

 applies to any and all of the formations which are later in time 

 than the Carboniferous period. Such an objection is to my mind a 

 feeble one ; one might almost as well say that a • postscript ' to a letter 

 includes all that the writer of the letter has since written. This, like 

 so many other questions of nomenclature, cannot be settled by mere 

 reference to a Latin dictionary: if it could be, a boy in a grammar 

 school might perhaps decide it for us. One feels, and every one who 

 has read Latin at all must feel, that in composition the prepositions 

 acquire a flexibility which they do not possess to the same extent 

 in their unagglutinated use. Surely ' post- ' does sometimes mean 

 ' coming after in importance ' as well as in sequence of time ; the 

 term in question therefore implies that the series to which it refers, 

 though having a sufficiently pronounced facies of its own to be 

 entitled to be regarded as a system distinct from, is yet in some 

 sense subordinated to, the Carboniferous system. Further, in con- 

 sidering the propriety of the use of the term now under discussion, 

 it should be borne in mind that the strata, to which the name ' Post- 

 Carboniferous ' is here applied, are recognized as falling into the 



1 Quart. Journ. Geol. Soc. vol. xxv. p. 171. 



