4:02 



BRADFORD ENCRINITES. 



[Oh. XX. 



ford in Wilts, to Tetbury in Gloucestershire. These calcareous tile- 

 stones are separated from each other by thin seams of clay, which 

 have been deposited upon them, and have taken their form, preserv- 

 ing the undulating ridges and furrows of the sand in such complete 

 integrity, that the impressions of small footsteps, apparently of crus- 

 taceans, which walked over the soft wet sands, are still visible. In 

 the same stone the claws of crabs, fragments of echini, and other 

 signs of a neighboring beach, are observed.* 



Great Oolite. — Although the name of coral-rag has been appropri- 

 ated, as we have seen, to a member of the Upper Oolite before de- 

 scribed, some portions of the Lower Oolite are equally entitled in 

 many places to be called coralline limestones. Thus the Great Oolite 

 near Bath contains various corals, among which the JEunomia radiata 

 (fig. 401) is very conspicuous, single individuals forming masses sev- 



Fig. 401. 





mums? 



Eunomia radiata, Lamouroux. (C'alamopliyllia, Milne Edw.) 



a. Section transverse to the tubes. 



b. Vertical section, showing the radiation of the tubes. 



c. Portion of interior of tubes magnified, showing striated surface. 



eral feet in diameter ; and having probably required, like the large 

 existing brain-coral (Meandrina) of the tropics, many centuries before 

 their growth was completed. 



Different species of crinoids, or stone-lilies, are also common in the 

 same rocks with corals ; and, like them, must have enjoyed a firm 

 bottom, where their root, or base of attachment, remained undis- 

 turbed for years (c, fig. 402). Such fossils, therefore, are almost con- 

 fined to the limestones ; but an exception occurs at Bradford, near 

 Bath, where they are enveloped in clay. In this case, however, it 

 appears that the solid upper surface of the " Great Oolite " had sup- 

 ported, for a time, a thick submarine forest of these beautiful zoo- 

 phytes, until the clear and still water was invaded by a current 

 charged with mud, which threw down the stone-lilies, and broke most 

 of their stems short off near the point of attachment. The stumps 

 still remain in their original position ; but the numerous articulations, 

 once composing the stem, arms, and body of the encrinite, were scat- 



F. Scrope, Geol. Proceed., March, 1831. 



