396 REV. A. IRVING ON THE DYAS (PERMIAN) 
one strongly with the close relationship that subsists between the 
Zechstein and the Carboniferous marine faunas; and a similar 
closeness of relationship between the floras of the Coal-measures 
and the Rothliegende is proved by an examination of Yon Hauer’s 
collection in the Reichsanstalt at Vienna. The use of the term 
‘ Post-Carboniferous,’ as I have defined it elsewhere*, seems therefore 
to be fully justified. 
GENERAL RELATION OF THE Dyas Group to THE O~pER MEMBERS 
oF THE Patmozorc SERIES. 
When one studies the rocks of the Dyas Group in the field, as L 
have done during the past summer in Germany, an impression takes 
hold of the mind that in the conditions of their deposition the strata of 
the German Dyas are far removed from any close relation with the 
Trias Group. This impression becomes more and more confirmed 
as one goes on, and to a degree which no amount of reading about 
them will enable an English geologist to quite understand. Not 
only is there a stratigraphical break, but a very marked petrological 
contrast between the two groups, which can hardly be understood 
from mere diagrams and descriptions. 
The Lower Rothliegende is for the most part a shore- and bay- 
deposit, fillmg in many cases the arms of the sea which washed 
the fianks of the more ancient Palzozoic land of Central Europe, 
lying very often unconformably upon the Coal-measures, in other 
cases upon the bituminous slates of the anthracite-bearmg Culm, 
again in other localities lying upon the schists or porphyries of 
the still older land, and in Saxony against the syenite itself. In 
northern Thuringia, for example, it consists of fine micaceous sands 
and marls, with a more or less shaly structure, enclosing in some 
of its beds angular fragments of quartz to such an extent as to 
give it the eharacter of a breccia, all its materials pointing to the 
waste of the adjacent land of Thuringia as their source. In this 
way materials were furnished and deposits formed, by which the 
productive coal-strata were covered up over many portions of what 
is now Central Europe. 
The Lower Rothliegende in some districts, as in Thuringia, passes 
upward into the granitic conglomerate of the “ Ober Rothliegende,” 
which marks a further and distinct stage in the progress of the 
degradation of the more ancient land of Thuringia, a true “ Gebirgs- 
insel” or mountain-island. In the vicinity of Hisenach, where I 
have examined it most in detail, | have found included fragments 
of granites, gneiss, quartz, mica-schist, diorite, quartzite, syenite, 
and even occasionally a lump of an older Paleozoic conglomerate ; 
and to these Prof. Senft of Eisenach adds lydite, hornstone, and 
felsite. Every one of these can be traced, as to their origin, to the 
rocks now exposed in Thuringia. As a rule, the granite-fragments 
are much more rounded than the fragments of the other rocks, a 
fact which can be explained by the greater distance of transport 
* Geol. Mag. Dee. ii. vol. ix. p. 494. 
