LOWER HELDERBERG ROCKS. 
ld>7 
PLATE II A. 
Fig. 1. A large individual, showing the anal or irregular side of the specimen, with nume¬ 
rous anal or interbrachial plates, the base of the proboscis, arms, etc. The upper 
part of the proboscis is covered by adhering stony matter. 
Geological position and locality. In the thin shaly intercalated layers of the 
Pentamerns limestone : Wheelock’s hill, Litchfield, Herkimer county. 
Mariaeriims paclijdactylus. 
Plate III. Fig. 1 - 4 a. 
Adinocrinites pohjdadylus , Schenectada Reflector, 1835. 
Astrocrinites packydadylus, Conrad in Catalogue, Ann. Rep. on Pal. N. York, 1841, p. 34. 
Astrocrinites packydadylus, Mather, Geol. Report 1843, p. 246. 
Body broadly turbinate or subhemispherical (the form presented depending 
much on the degree of pressure it has sustained in the rock). Surface 
ornamented by strong radiating ridges from the centre of the plates, 
which, combining, give the whole a reticulate aspect, and each plate a 
star-like appearance : this character extends not only to the plates of 
the body, but to the brachial plates, and beyond the bases of the 
auxiliary arms. Basal plates wider than long, with prominent ridges 
extending to the upper edges, and a thickened lower margin. First 
radial or first costal plates as wide as long, four heptagonal and one 
hexagonal, marked with strong rays near the margin, and a strong ridge 
through the length of the plate in the direction of the arms. Second 
radial plates heptagonal, as long as wide, smaller than the first radials, 
and marked in the same manner. Third radial plates smaller than the 
second; three of them heptagonal, the others probably of the same form. 
Interradial plates small, strongly angulated upon the surface. Brachial 
plates heptagonal, two upon each third radial, and each succeeded by 
two other plates, which are slightly divergent and admit between them 
a row of smaller plates : again bifurcating upon the third brachial plate, 
the outer plate on each side gives origin to the auxiliary arm, and the 
two inner ones converge over the intercalated range of smaller plates, 
giving origin in direct line to the double series of plates which compose 
the main arm. 
