FOSSIL FAUNA. 95 



PLATE XXXVIII. 



Fossil Corals, and Coral Marbliss. 



Fig. 1, is a polished slab of the carboniferous limestone, well known as the Kilkenny marble, 

 and much used for chimney-pieces. The figures exposed on the surface are produced 

 by sections of enclosed corals (some species of Cyathophyllum), which are transmuted 

 into white calcareous spar. 



Fig. 2. A coral of the same kind {Cyathophyllum turbinatum), from the mountain limestone of 

 Derbyshire.) 



Fig. 3. A polished slice of Derbyshire marble, the markings on which are derived from sections 

 of enclosed branches of corals {Syringopora), resembling that figured in PI. XXXI V. 



Fig. 4. An elegant compound coral, called « Spider-stone " by collectors {Astrea arachnoides, 

 of Dr. Fleming) ; from Wiltshire : the geological habitat uncertain ; probably the 

 Oolite. 



Fig. 5. This specimen appears to be a cluster of corals belonging to the genus Cyathophyllum. 



Fig. 6. A magnified sketch of one of the cells of fig. 4. 



Fig. 7. A polished transverse section of a coral ; the precise relation of this species is not certain. 



Fig. 8. This is a very abundant coral in some of the beds of mountain limestone, {Lithodendron 

 fasciculatum, of Phillips.) The specimen figured is from Clifton, near Bristol. The 

 marble cups, and other ornaments, manufactured from the rocks near that place, 

 often exhibit sections of this species. 



Fig. 9. A mass of coral from Ingleborough, {Cyathophyllum fungites.) 



Fig. 10. A polished slice of a beautiful marble richly marked by the sections of the enclosed 



corals {Astrea undulata, of Dr. Fleming) ; from Switzerland : probably from the 



Oolitic or Jurassic formation. 



Fig. 11. Vertical section of a fossil coral, showing the transverse arrangement of the internal cells. 



Fig. 12 & 13. These specimens are polished sections of a very beautiful compound coral {Astrea 

 Tisburiensis, of Miss Benett), which occurs in a sUicified state in the Portland beds 

 that are quarried at Tisbury, in Wiltshire. Masses of chert (a kind of coarse 

 silex or flint), wholly made up of this coral, are often met with, and when sliced 

 and polished are extremely beautiful and interesting; the originally calcareous 

 fabric of the zoophytes being perfectly transmuted into silex, and the interstices 

 filled up with a similar substance, but of a different colour. ' 



' Specimens of the Tisbury Astrea, and of most if not all of the coralline marbles figured and described, may be obtained 

 of Professor Tennant ; and also vases, &c. of the rarious marbles of Derbyshire. 



