380 OLDER MESOZOIC FLORAS OF UNITED STATES. 
excellent state of preservation. It is of a nearly uniform black color, 
thoroughly silicified, with a cherty aspect in places, and high specific 
gravity. The total weight is 34.93 kilograms. 
Its maximum height is 40 cm., but the base is 5 cm. lower in the 
middle than elsewhere, and the upper fracture is oblique both ways, 
so that the length of the minor face is only 28 cm., and that of the 
side opposite 32cm. The partial major axis, which is nearly the same 
at all points, is about 26 cm., and the minor axis varies from 20 to 24 
cm., being greatest near the base. The partial girth (exclusive of the 
broken inner face) is from 58 to 60 cm. 
The organs of the armor are slightly declined throughout the entire 
length, the angle diminishing upward. They were probably hori- 
zontal on the lost upper portion of the trunk. The leaf scars are 
arranged in two regular and distinct spiral rows around the trunk, 
those ascending from left to right forming an angle of about 30°, 
. those from right to left of about 45° with the vertical axis. One of 
the former would make a revolution in about 1 meter, one of the 
latter in about 65 cm. 
The scars are of about the normal size and nearly triangular, rarely 
somewhat arched above, but sometimes concave, soas to appear inversely 
heart-shaped. The upper side of the triangle is nearly horizontal and 
the other two sides are in the line of the two rows of scars respectively, 
what may be called the right side being steeper than the left, and the 
lower angle a little to the right of the center of the upper side. The 
sides are thus of slightly different lengths, the upper longer than either 
of the others and the left longer than the right. Where the upper 
side is 20 mm., which is about the average, the left side will be 18 mm. 
and the right side 16 mm. The distance from the lower angle to the 
center of the upper side averages about 15 mm. 
The leaf bases are always present at a certain depth, usually 1 cm. 
but sometimes 83cm. or more. Their summits are nearly level or 
slightly concave, and there seems to be a joint at which they are usually 
disarticulated. They present a roughened or spongy appearance with- 
out pits or bundle scars, but in some cases they seem to be traversed 
by thin longitudinal dikes crossing one another at varying angles. 
The walls are very thick, 5 to 8 mm., with large thickenings in the 
angles of the scars, often as large as the scars themselves. The scars 
are lined with a layer 0.5 mm. thick, the union of which with the walls 
can generally be seen; otherwise the walls are nearly homogeneous 
and rough on the outer edges. 
Reproductive organs are very abundant and well developed. There 
is practically one in the axil of every leaf. They stand for the most part 
directly over the upper side of the scar, and sometimes depress that 
side, but usually the effect is confined to a considerable thinning of the 
