FOSSILS OF NEW SOUTH WALES. WAL: 
On this ground, and moreover, an actual resemblance to the plates of certain encrinites, 
particularly the echino-encrinites and some others, he feels assured that they are crinoidal. 
The three specimens observed, although so unlike in form, may therefore have belonged 
to a single species, as the dissimilarity is not greater than is common, The mark- 
ings of the three are identical in character, and the specimens were all found at the 
same locality. The only objection I know to their being parts of a single species is the 
fact that the triangular specimen is much thicker than either of the other two. The 
following are the characters of each. We retain the generic name proposed in the Ame- 
rican Journal of Science, and call the species to which the pentagonal plate, and one or 
both of the others belonged, 
PEeNTADIA Corona.—Plate 10, Figure 10, 10 a, 0, c. 
Figure 10, plate 10.—Discoid, five-sided, (or approaching ten-sided,) angles and edges 
rounded. Upper and under surfaces correspondingly radiato-undulate, consisting of five 
triangular areas and five intermediate concave depressions. Above, delicately marked con- 
centrically with fine crenulate ridges, constituting a series of concentric pentagons (about 
thirty in all), the ridges of the inner seven or eight, coarser than the following. Diame- 
ter 2 inches; thickness 13 lines.—Figure 10 is a view of the sculptured surface, and 10 
a, a section across from @ to 6, showing the thickness ; 10 a, opposite surface ; 6, enlarged 
view of inner ridges. ; 
The angles of the concentric pentagons are situated in the medial line of each penta- 
gonal area, and in four of the intermediate depressions there is at middle a re-entering 
angle (A-like) to each pentagon. One of the depressions, in which there are not these 
re-entering angles, differs from the others in being broader and less abrupt, the triangular 
areas either side almost sloping into it and thus forming it. The outer two-thirds of the 
upper surface have the delicate ridges crossed at right angles by very fine parallel lines, 
and this produces the appearance of crenulation, 
Figure 11, plate 10.—Reniform, thin, arcuately flexed; resembling a single segment 
of the preceding, enlarged by a wing-like dilatation of one side, the projection néarly as 
large as the segment, and thus producing the reniform shape. Breadth 1% inches ; 
length ~ of an inch; thickness at middle 1 line, much less so at the margin. 
The minute ridges meet in an angle (that of a pentagon) along the middle of one lobe, 
and on either side of this lobe are flexed A-shape, though not regularly so except towards 
the posterior margin. The other lobe (the wing-like enlargement alluded to) has the same 
parallel ridges on the surface, but they do not meet in an angle. 
Figure 12, plate 10.—Trigonal, rather thick, margin rounded, not alate. Breadth 
1 inch; thickness Z inch.’ 
The surface, like that of the last, is marked with two sets of lines meeting in the 
angle of a pentagon, as in one segment of the pentagonal specimen. The line in which 
the angles lie is to one side of the middle of the triangle, so that the surface on one side 
is twice as broad as that on the other; and on each side the parallel ridges have each a 
re-entering angle (A-shape). : 
Pentadia.—Amer. Jour. Sci., ii. Ser., iv. 152. 
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