LOWER HELDERBERG ROCKS. laT 



Lepadocrinus gebhardi ^ Conrad). 



Plate VII. Fio. 1 - 20. 



SYNONYMES AND REFERENCES. 



Lepocrinites gebhardi : Conead, Annual Report on PaliBontology of New-York, 1840, p. 207. 

 _ _ Vanuxem, Geo!. Report of Third District of New-York, 1842, p. 117, f. 4. 



— — Mather, Geol. Report of First District of New- York, pp. 346 & 247, t. 4, 5. 



Body oblong, oval or ovoid, compressed at the sides, unsymmetrical, being 

 mucb more gibbous on the lower part of the posteal or ovarian side 

 than on the opposite ; usually abruptly rounded above and obliquely 

 subtruncate below. The basal series consists of four unequal plates, 

 1, 2, 3, 4 ; the second series of five, 5, 6, 7, 8, 9 ; the third series of 

 foiu", 10, 11, 12, 13 ; and the fourth or supraovarion of five, 14, 15, 

 16, 17, 18 : making the formula B, 4 + 5 + 4 + 5. The supraovarian 

 plate extends downwards on each side, half enclosing the aperture : 

 ovarian and circa-ovarian plates unknown. Plates of the summit un- 

 known. A reniform depression and anal pore a little upon the left of 

 the centre. 



Akms four, consisting of an anterior and posterior pair, which lie in 

 shallow grooves along the rounded angles of the body, reaching nearly 

 or quite to the base, and rising much above the surface of the adjoining 

 plates ; the anterior pair nearer to each other than the posterior pair, 

 extending downward nearly to the base. The arms are composed of a 

 double series of plates, each alternate one being similar. A range of 

 minute ossicula extends along the centre of the groove between the 

 plates of the arms, from which diverges a shorter range to the sinuosi- 

 ties of the arms, where originate the fingers or pinnules. Fingers 

 slightly alternate, but preserving the appearance of being in pairs or 

 opposite ; composed of a double series of ossicula, closely interlocking 

 at their contiguous wedgeform margins, and standing erect from the 

 surface of the body, or lying close upon the arms and infolded in pairs 

 beneath each other. Surface of plates granulate ; the granulations 



