216 



LYELL'S ELEMENTS OF GEOLOGY. 



Bradford Encrinites. 



enjoyed a firm bottom, where their root, or base of attachment, 

 remained undisturbed for years (c. Fig. 202.) Such fossils, 



Fig. 202. 



Apiocrinites rotundas, or Pear Encrinite ; Miller. Fossil at Bi-adford, Wilts, 



a. Stem of Apiocrinites, and one of the articulations, natural size. 



b. Section at Bradford of great oolite and overlying clay, containing the fossil 



encrinites. See text. 



c. Three perfect individuals of the Apiocrinite, represented as they grew on 



the surface of the Great Oolite. 



d. Body of the Apiocrinites rotundus. 



therefore, are almost confined to the limestones ; but an excep- 

 tion occurs at Bradford, near Bath, "where they are enveloped in 

 clay. In this case, however, it appears that the solid upper sur- 

 face of the " Great Oolite" had supported, for a time, a thick 

 submarine forest of these beautiful zoophytes, 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 com- 

 posing the stem, arms, and body of the zoophyte, were scattered 

 at random through the argillaceous deposit in which some of 

 them now lie prostrate. These appearances are represented in 

 the section Fig. 202., where the darker strata represent the 

 Bradford clay, a member of the Forest marble (e. Table, p. 213.). 

 The upper surface of the calcareous stone below is completely 

 incrusted over with a continuous pavement, formed by the stony 

 roots or attachments of the Crinoidea ; and besides this evidence 

 of the length of time they had lived on the spot, we find great 

 numbers of single vertebrse, or circular plates of the stem and 

 body of the encrinite, covered over with serpulse. Now these 

 serpulae could only have begun to grow after the death of some 

 of the stone-lilies, parts of whose skeletons had been strewed 

 over the floor of the ocean before the irruption of argillaceous 



