Chap. XIII.] 
PERMIAN ROCKS IN BRITAIN. 
327 
red rocks above that rock, all the members of the group are united by pa- 
laeontological evidences. 
In a general sense it may indeed be said that the Permian of Germany 
is a lower or palaeozoic ' Trias/ the central mass of which is the Zechstein 
with red sandstone above and below it ; whilst the Upper or Secondary 
' Trias ' is also marked by its middle limestone, the Muschelkalk, with its 
underlying Bunter Sandstein and its overlying Keuper marls. 
Whether the lower ' Bunter ' be abstracted from the Trias or not, let 
me again call attention to the fact that, whilst the Permian and Trias are 
conformable to each other, and exhibit nowhere in Germany any of those 
disseverments which mark the separation of the Lower from the Upper 
Coal of the Continent, their respective fauna and flora are, according to the 
present state of knowledge, entirely dissimilar. The Permian exhibits the 
last traces of primeval life, whilst the Trias is charged with Secondary 
Plants and Animals entirely distinct from all those which preceded them. 
Permian Rocks of Britain Sfc. (see No. 8 of the Map *). — The Per- 
mian rocks of Britain, where they are most clearly developed, consist, in 
ascending order, of the lower red and yellow sandstones and conglomerates, 
the equivalents of the Eoth-liegende ; the Marl-slate and Magnesian Lime- 
stone, the equivalents of the Kupfer-Schiefer and Zechstein ; followed by 
certain bands of red sand and marl, as expressed in the preceding diagram. 
The best types, particularly of the calcareous or central portion of this suc- 
cession, are to be seen in the counties of Durham, York, and Nottingham, 
where they were long ago admirably described by Professor Sedgwick f , 
and compared by him with the German deposits of like age. Let us there- 
fore first treat of the group in those districts where the clearest relations of 
its chief parts are best exhibited. 
In Durham the lower sandstone is well exhibited at Clacksheugh, three miles 
west of Sunderland^ where, on the left bank of the Wear, its lowest portion 
* The Permian rocks, as defined in the work on ful Knowledge (see also new editions, 1856 and 
Russia, were first laid down on a Geological Map 1866, published by Stanford), 
of England constructed by myself in 1843, and t See Sedgwick on the Magnesian Limestone 
published by the Society for the Diffusion of Use- (Trans. GreoL Soc, 2nd series, vol. iii. p. 37). 
