lxxvilli DESCRIPTIVE REMARKS. 
thus, Platysomus, and Acrolepis (the same forms being frequent in 
England, Germany, and Russia). 
These fossil fish are chiefly found in the division of the Permian 
called Kupfer-Schiefer, underlying the Zechstein in Germany; and in 
England they are met with in the equivalent deposit, the Marl slate. 
Some small examples of Palgoniscus and Acrolepis have also been de- 
scribed from the Upper beds of the Magnesian Limestone of Durham.* 
The Repritra discovered in British Permian strata include two 
species of Proterosaurus, from the Marl slate, Durham, referred to the 
Lacertian order, and allied to P. Spenert of Von Meyer, from the 
Kupfer-Schiefer of Thuringia; also two species of LasyrinrHopont 
Reprites, named Leptosaurus Duffii, from similar slate near Durham ; 
and L. dasyceps from Permian Sandstone, Kenilworth. 
In closing this brief sketch of the Permian fossils, we cannot do 
better than quote the following appropriate remarks of the late Sir R. 
Murchison, in his last edition of Siluria: ‘‘ The mass of the organic 
remains of the Permian group constitute a remnant only of the earlier 
animals whose various developments we have followed in the preceding 
pages. They exhibit the last of the successive changes which these 
creatures underwent before their final disappearance. The dwindling 
away and extinction of many of the types which were produced and 
multiplied during the anterior epochs already announce the end of the 
long Paleeozoic period.” t 
The following Table, showing the number of species belonging to 
the various classes of Plants and Animals in the Paleozoic Rocks of 
Great Britain, is copied from Mr. Etheridge’s elaborate communication 
to the Geological Society of London in 1867. 
(Certain discrepancies between the numbers of species in the Silurian 
column of this Table and that before given at page 1., may, per- 
haps, be accounted for by the difference of time at which they were 
respectively published.) 
* Siluria, 4th edition, p. 342, 
+ Ibid. p. 344. 
f‘ Onthe Physical Structure of West Somerset and North Devon, and on Devonian 
Fossils,’ &e., Journ. Geol. Soc., vol. xxiii., p. 615. 
