139 
ground enriched by numerous undulating striee, some of which unite 
with the rays of which the stars are themselves composed. At Planche 
XLl. Fig. 6 , a. and 6, b, is a fossil which also bears a general resem- 
blance to our fossil, but differs from it in having, instead of undulating 
lines, superadded rays, which diverge in straight lines from the central 
star. The fossil, Planche XLL Fig. 3 , which he describes, Astroite ma- 
mellone, avec des rayons en t^te de M6duse qui partent de chaque 
mamelon, would, if reduced to a smaller size, approach much nearer 
to our fossil than do either of the others. 
The specimen, Plate XII. Fig. 4, like the former, is highly in- 
teresting, from the difficulties which accompany an inquiry into its 
original nature ; rendered still greater, by the want of any analogous 
bodies, with which any instructive comparison might be made. This 
fossil, also obtained from St. PeteFs Mountain, is formed of the same 
substance as the former. The organic part of this fossil is confined 
to the superior part, and to a small cleft on one side, and is composed 
of a surface so finely granulated, as to give an appearance like the 
pile of velvet. On this general surface are disposed, in small de- 
pressions, oblong bodies, in an oblique but almost horizontal direction, 
each body being composed of six similarly formed tubes or fibres, 
from an eighth to a quarter of an inch in length. Most of these bodies 
taper a little, at their more detached ends, and thereby obtain somewhat 
of a conical shape. 
A slender fibre branches from about the centre of some of these 
bodies, and is inserted in the side of the adjoining depression. In 
some, there are two of these fibrous connecting processes, and in others, 
no traces of them are observable. But from considering the delicacy 
of their structure, and their liability to be broken, and observing in 
that lower stratum, at the one end of the specimen, which has been 
protected in a considerable degree from injury by the superincumbent 
layer, that this slender process is attached to every one of these cylin- 
drical bodies, I think there is very little reason to doubt that this 
