280 FISHES IN MAGNESIAN LIMESTONE, 
Fishes of the Magnesian Limestone, 
or Zech stein. 
The Fishes of the Zechstein at Mansfeld and 
Eisleben have been long known, and are com- 
mon in all collections ; figures of many species 
are given by M. Agassiz. Examples of the 
Fishes of the Magnesian limestone of the north 
of England, are described and figured by Pro- 
fessor Sedgwick, in the Geol. Trans, of London, 
(2d Series, Vol. iii. p. 117, and PL 8, 9, 10). He 
states in this paper (p. 99), that the occurrence of 
certain Corals and Encriniles, and several species 
of Producta, Area, Terebratula, Spirifer, &c. 
shews that the Magnesian limestone is more 
nearly allied in its zoological characters to the 
Carboniferous order, than to the calcareous for- 
mations which are superior to the New red sand- 
stone. This conclusion accords with that which 
M. Agassiz has drawn from the character of its 
fossil Fishes. 
tail is regular and symmetrical. In certain bony Fishes of the 
secondary period, the upper lobe of the tail is partly covered with 
scales, but without vertebrse. The bodies of all these Fishes also 
have an integument of rhomboidal bony scales, covered with 
enamel. 
No species of Fish has been found common to the Carboni- 
ferous group, and to the Zechstein or Magnesian limestone ; but 
certain genera occur in both, e. g. the genus Palseoniscus and 
Polypterus. 
