410 OLDER MESOZOIC FLORAS OF UNITED STATES. 
side of the two specimens. The interval between them was of course 
larger than it was possible to place between the two figures. .Pl. CLI 
shows the other broad side of No. 500.56, and Pl. CLIII gives the 
upper transverse fracture of No. 500.79. 
CYCADELLA Gravis Ward. 
PI. CLIV. 
- 1900. Cycadella gravis Ward: Proc. Wash. Acad. Sci., Vol. 1, p. 277. 
Trunk small (12 cm. high, 8 by 13 cm. in diameter), conical-flattened, 
rounded at the summit, laterally compressed, unbranched; rock very 
hard, coarse-grained, of a gray color and very high specific gravity; 
organs of the armor upwardly appressed, especially on one side; rows of 
scars from left to right making an angle of 35°, those from right to left 
of 50°, with the axis; scars subrhombic, 18 to 22 mm. wide, 8 to 10 mm. 
high; leaf bases on the side of the specimen appressed to the trunk 
but exposed at their summits and on their lower sides, the keel distinct, 
rough or honeycombed on the exposed ends, but on fresh fractures fine 
in structure and white-punctate with small, narrowly elliptical, white 
pores appearing as short white lines; vascular bundles faintly visible, 
forming a row part way round the petiole on the side next the trunk; 
walls 1 to 2 mm. thick, striate with alternating light and dark lines; 
reproductive organs few, poorly developed, sometimes raised, 2 by 
3 cm. in diameter, the interior porous or heterogeneous; armor 2 cm. 
thick, joined to the axis by a definite line of appreciable thickness 
(libro-cambium layer), wood 2 cm. thick; cortical parnechyma 1 cm. 
thick, of coarse structure; fibrous zone 1 cm. thick, consisting of two 
rings of equal thickness separated by a light-colored band, the struc- 
ture radially disposed; medulla 2 by 6 cm. in diameter, hard and coarse 
with white punctations or variously shaped markings. 
This small specimen, No. 500.63 of the collection, is so totally differ- 
ent from all the rest that it was necessary to regard it as constituting 
a species by itself. It weighs 1.5 kilograms and has the highest 
specific gravity observed, feeling almost like heavy spar, whence the 
specific name. , 
Pl. CLIV, Fig. 1, shows the best side, and Fig. 2 the base. 
CYCADELLA VERRUCOSA Ward. 
Pls. CLV-CLVII. 
1900. Cycadella verrucosa Ward: Proc. Wash. Acad. Sci., Vol. I, p. 278. 
Trunks large (30 to 40 cm. high, 20 to 30 cm. in larger diameter), 
obovate, contracted at the base, much laterally compressed, 
unbranched or with a few small secondary axes; rock hard and fine at 
least in the interior, light colored or brown on weathered surfaces, 
