ON THE DYAS (PERMIAN) AND TRIAS OF CENTRAL EUROPE. 389 
29. On the Dyas (Permian) and Trias of CuntraL Evropr, and the 
true Divistonan Line of these two Systems. By the Rev. A. 
Irvine, B.Sc., B.A., F.G.S. (Read April 23, 1884.) 
In bringing this subject before the Society, it is my intention merely 
to follow up and supplement that treatment of the questions involved 
which, through the courtesy of the Editor of the Geological Magazine, 
I was able to apply to them (more especially for the British rocks) 
during the year 1882. I shall assume that what I have written in 
that periodical is familiar, or at any rate accessible, to all Fellows 
of the Society who are interested in the question herein discussed. 
This paper was written, for the most part, last summer in Germany, 
and some of the facts were given briefly to Section C of the British 
Association at Southport. I must express my grateful acknowledg- 
ment of the aid which has been courteously given me by geologists of - 
high standing on the Continent, in particular by Prof. Geinitz, 
Dr. Franz Ritter von Hauer, and Dr. Liebe. I am also greatly 
indebted to the Museums of Dresden and Freiberg, and to the Geo- 
logische Reichsanstalt in Vienna. 
Without committing myself to a definite advocacy of a substitution 
of the name Dyas for the name Permian, I must be allowed briefly 
to point out that it is not a mere question of names. The Permian 
system of Murchison was essentially a tripartite one, and in applying ~ 
it to the rocks of central Europe (and to those of the British area) 
he raised the question of the true position of certain thin-bedded 
sandstones and marls (Sand- and Mergel-schiefer of German writers), 
which he (following some German writers) named ‘“ Bunter- 
schiefer.” In so doing he necessarily raised the question of the true 
divisional line between the Paleozoic and Mesozoic Series. Whatever 
the relative values of the names ‘‘ Dyas ” and ‘“‘ Permian ” may be, 
the facts connoted by those names respectively are of great im- 
portance in settling a vexed question of classification. It is beside 
the point to say that if the upper boundary of the Zechstein shows 
signs of denudation, there may have been, by a guondam upward 
extension of the Dyas, an original “Trias” of post-Carboniferous 
age: the question before us is, What is the true age of the “ Bunter- 
schiefer”? And it is impossible to discuss this without also con- 
sidering the further question of the conformability or unconform- 
ability of the Dyas or Trias of Central Europe, and this of course 
involves us of necessity in the question of the true upper limit cif 
it can be drawn) of the Paleozoic Series. 
This paper has originated simply in an attempt to answer the 
question as to the true age of the Bunterschiefer, and to do so as far 
as possible from direct evidence in the field. 
The name Dyas (Avds), which was first proposed by M. Marcou 
in 1859, was adopted by Geinitz, in preference to the several geogra- 
