oe 
698 STRATIGRAPHICAL GEOLOGY.  [Boox VI. 
‘The cephalopods embrace representatives of both the tetrabranchiate 
families of Nautilids and Ammonitids. Among the Nautilids are 
the genera Clymenia (50 species), an especially abundant form in 
some of the Upper Devonian shales and limestones, Gyroceras, 
Orthoceras (180 species), Cyrtoceras (60 species), and Gomphoceras. 
The great family of the Ammonites had in the Devonian waters 
representatives of the more abundant coiled forms in the character- 





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7) hj 

Fia. 830.—DEvoNIAN Fosstus. 
a’, Stringocephalus Burtini (Def.) ; a’, Do. lateral, and a’, Do. internal view ; b, Uncites 
eryphus (Def.); ¢, Spirifera disjuncta (Sow.) ; d, Calecola sandalina (Linn.); d*, Oper- 
eular lid of do.; e, Cuculleea Hardingii (Sow.); /, Megalodon cucullatus (Sow.). 
istic genus Goniatites (168 species), and of the straight forms in 
Bactrites (9 species). In the Devonian rocks of Central Hurope 
scanty remains of the great fish fauna of the Old Red Sandstone 
have been found, more especially in the Hifel, but seldom in such a 
state of preservation as to warrant their being assigned to any 
definite place in the zoological scale. Recently, HE. Beyrich has 
described from Gerolstein in the Eifel an undoubted species of 
Pterichthys, which, as it cannot be certainly identified with any 
known form, he names P. Rhenanus. A Coccosteus has been 

