Hudson-river group. 
277 
Genus DISCOPHYLLUM. 
[Greek, JitfxoS, a disc, and <puXXov, a leaf.] 
Character. Discoidal, flattened, rays or dissepiments numerous, proceeding from the 
centre; body of the fossil apparently semicalcareous or corticifemus ; margin well defined. 
From the semi-metamorphic condition of the rock, it is impossible to determine whether 
this body was calcareous; but it appears to have been otherwise, 
335. 1. DISCOPHYLLUM PELTATUM (n. sp.). 
Pl. LXXV. Fig. 3. 
Body consisting of a somewhat circular flattened expansion, composed mainly of radiating 
fibres, which enlarge as they recede from the centre, and terminate in a thickened border. 
This fossil appears to have consisted, originally, of a semi-hard circular or oval body, 
with firmer rays, reaching nearly or quite to the margin. The body becomes thicker and 
apparently harder towards the margin, and the rays are nearly concealed in its substance. 
This disc may have been attached by a smaller stipe, proceeding from the lower side, 
some obscure evidence of such an appendage existing. 
Two specimens of this peculiar fossil have been found : one in 1822, and the other a 
few years since, showing that it is an exceedingly rare form. It is quite unlike any other 
fossil known in our older strata. 
Position and locality. This species occurs in the partially metamorphic arenaceous shales 
of the Hudson-river group, near the Nail Factory, below Troy, where the only known 
specimens have been found. ( Cabinet of Troy Lyceum; Cabinet of Prof. Cook.) 
336. 1. ( Undetermined ,) 
Pi,. LXXV. Fig. 4. 
The specimen figured is an impression of the outer surface of some incrusting coral, 
frequently found attached to the shell of the Orthoceras coralliferum. It appears to be 
composed of large elevated points or stars, with an intermediate granulated or papillose 
surface. It is usually obscure, or very imperfectly preserved, the more elevated {joints only 
being visible. The figure is of the natural size, from a specimen adhering to an Orthoceras. 
This coral is also represented in an imperfect specimen attached to another shell of the 
same species (Plate lxxxvi, fig. 1). It is sometimes found under other circumstances, and 
attached to other shells, but always so obscurely preserved that its characters cannot be 
well determined. 
Position and locality. This coral is known in many localities of the Hudson-river group, 
widely separated from each other. It has been found at Turin, Pulaski, Loraine; near 
Rome,- in Oneida county ; in the altered shales near Waterford, and in the same situation 
in Ohio, near Cincinnati.. (State Collection.) 
