350 DIVISION OP THE PERMIAN GROUP. |"Ch. XXIII 



CHAPTER XXIII. 



PERMIAN OR MAGNESIAN LIMESTONE GROUP. 



Possils of Magnesian Limestone and Lower New Red distinct from the Triassic— 

 Term Permian — English and German equivalents — Marine shells and corals of 

 English Magnesian limestone — Palasoniscus- and other fish of the marl slate — 

 Thecodont Sauriansof dolomitic conglomerate of Bristol — Zechstein and Rothlie- 

 gendes of Thuringia — Permian Flora — Its generic affinity to the carboniferous 

 — Psaronites or tree-ferns. 



When the use of the term " Poikilitic" was explained in the last 

 chapter, I stated, that in some parts of England it is scarcely possible to 

 separate the red marls and sandstones so called (originally named " the 

 New Red"), into two distinct geological systems. Nevertheless, the 

 progress of investigation, and a careful comparison of English rocks be- 

 tween the lias and the coal with those occupying a similar geological 

 position in Germany and Russia, have enabled geologists to divide the 

 Poikilitic formation ; and has even shown that the lowermost of the two 

 divisions is more closely connected, by its fossil remains, with the car- 

 boniferous group than with the trias. If, therefore, we are to draw a 

 line between the secondary and primary fossiliferous strata, as between 

 the tertiary and secondary, it must run through the middle of what was 

 once called the " New Red," or Poikilitic group. The inferior half of 

 this group will rank as Primary or Paleozoic, while its upper member 

 will form the base of the Secondary series. For the Lower, or Magne- 

 sian Limestone division of English geologists, Sir R. Murchison proposed, 

 in 1841, the name of Permian, from Perm, a Russian government where 

 these strata are more extensively developed than elsewhere, occupying an 

 area twice the size of France, and containing an abundant and varied 

 suite of fossils. 



Prof. King, in his valuable monograph* of the Permian fossils of Eng- 

 land, has given a table of the following six members of the Permian 

 system of the north of "England, with what he conceives to be the corre- 

 sponding formations in Thuringia. 



North of England. Thuringia. 



1. Crystalline or concretionary, and 1. Stinkstein. 



non-crystalline limestone. 



2. Brecciated and pseudo-brecciated 2. Rauchwacke. 



limestone. 



3. Fossiliferous limestone. 3. Dolomit, or Upper Zechstein. 



4. Compact limestone. 4. Zechstein, or Lower Zechstein. 



5. Marl-slate. 5. Mergel-schiefer, or Kupferschiefer, 



6. Inferior sandstones of various col- 6. Rothliegendes. 



ors. 



* Palseontographical Society, 1850, London. 



