314 OLDER MESOZOIC FLORAS OF UNITED STATES. 
conclusion in this case. If, however, I must judge from the speci- 
mens, I think his fig. 98 is ideal in large part and is a restoration that 
is erroneous. 
The specimen of Z. cércularis, given in Fig. + of Pl. XLVII, and 
which, as stated, is probably the basis of Emmons’s description quoted 
above, differs from the forms he calls Z. ellipticus. The imprint is 
on a piece of rather soft shale, which, in the vicinity of the fossil, has 
a tendency to split off. It apparently has split away to some extent, 
carrying off a portion of the disk-like fossil, so that at present only 
a portion of the imprint is shown. Evidently it was originally a com- 
plete circle, 4 cm. in diameter. This circle has at its circumference a 
depressed cord-like groove, which corresponds to the cord-like ele- 
vated line seen at the tips of the scales of Z. ellipticus. On the 
exterior of this depression there is a faint indication of a ragged 
fringe of epidermal tissue, but there is nothing definite like the circle 
of triangular teeth given by Emmons. Within the marginal circle 
there are narrow wedge-shaped imprints of the same general character 
as those of the scales of Z. ellipticus, but much smaller and less dis- 
tinct. These imprints converge to the center of the circle, touching 
one another, so that they completely fill the circular space which 
forms the disk composing the fossil. The imprints of the scales seem 
to have keels like those of Z. eldipticus, but they are much less distinct 
and more slender. These imprints of scales disappear under an irreg- 
ularly shaped patch of coal, in the form of a structureless layer, which 
is located around the center of the disk. This layer once evidently 
extended over the whole disk, but it has suffered much from handling, 
so that only a patch of it remains toward the central part of the disk. 
It is thickest on its outer edges, and thins away to nothing in the 
center of the disk, where the scale shows through it. There is on 
these imprints of scales no epidermal tissue like that on the scales of 
L. ellipticus. The dark-colored, flattish, or circular body, mentioned 
by Emmons as connected with the central termination of the scales, is 
apparently this patch of coal. It'presents no appearance of being 
a fruit or seed, but is without structure, and has no significant shape. 
The great variation in the diameter of the disks mentioned by 
Emmons, varying from half an inch to 7 inches, and the fact that 
three concentric tiers of scales were found on one disk, indicate that 
the plant is not a cone or inflorescence. Heer gives, in Flor. Foss. 
Helvetie, Die Pflanzen der Trias, some figures of Equisetum that may 
throw some light on these North Carolina plants. In pl. xxvi, fig. 2, 
he gives a diaphragm of Equisetum with its disk striated by lines nar- 
rowing from the circumference, converging toward the center. The 
outer margin of the disk has three concentric rows of triangular teeth. 
Pl. xxvii, fig. 2, gives a diaphragm in the form of a disk composed of 
ribs, which radiate from a central area, bare of carbonaceous matter, 
