1878. | 325 [Lesquereux, 
zontal direction, four millimeters in the vertical one, also covered with a 
thin layer of opaque coaly bark. 
This species seems to represent a floating rather than a creeping plant, 
for no traces of appendages like radicles or their scars can be observed 
upon any of the specimens. The prolongation of the stem into a broad, flat, 
thick leaf, seems to indicate that kind of growth in water, as it appears to 
serve as a support to the plants on the surface of the water. 
The cylindrical part of fig. 3, deprived of its thick bark, which is left on 
both borders, evidently shows, not merely the relation, but the identifica- 
tion of Cordaites with Artisia, an identification which is still more closely 
seen upon a number of other larger stems of Cordaites, one of them figured 
Pl. LIL, fig. 2. It shows a double layer of bark which, whenever it is de- 
stroyed, distinctly exposes the horizontal ribs of Artista. This fragment 
appears articulate, and marked on one side of the articulation by a large, 
protuberant scar of a branch, while on the other side it shows the semi-lunar 
scar of a leaf. No trace of articulation has been until now remarked upon 
stems of this kind, at least none is mentioned in the work of Grand’ Eury, 
who has so remarkably illustrated this genus. The specimen bears, just 
near the branch-scar, a bundle of narrow leaves of Tenitophyllunm con- 
textum. Pl. LIII, fig. 2,—but the bundle does not touch by its base 
the scar of the branch, nor does it appear to be in connection with 
it, and as the specimen, a large piece of shale, is covered with bundles 
of the same leaves, I do not consider them as related to this stem. Another 
specimen, a branch twenty-two centimeters long, three and a half centi- 
meters broad, convex or half flattened, whose surface is partly covered 
with the coaly layer and the distinct semi-lunar scars of leaves, six milli- 
meters broad, shows, where deprived of its bark, or upon more than the two- 
thirds of its surface, the distinctly marked cross ribs of Artista. These ribs 
are variable in width from one to two millimeters, parallel, sometimes 
slightly undulating in their borders, but traversing right across the tumes- 
cent obtuse scars of the leaves, without any deviations in their direction, 
nor any kind of branching which could indicate the passage of vessels of 
leaves into the subcortical cylinder. On one of the borders of the branch, 
the bark either flattened, or cut lengthwise like that of Pl. L, fig. 3, is 
half a centimeter thick. The surface coal layer, however, is not more than 
one-fourth or scarcely halfa millimeter thick. That therefore the Artisia, 
or at least most of the stems described under this name, are the woody cyl- 
inder of Cordaites is established beyond a doubt by these specimens. 
I cannot assert from the examination of my specimens that species of Ar- 
tisia may not be referable to Dadoxylon representing Conifers. But I have 
not seen as yet any branches of Artista which might be separated from 
the Cordaites ; andif Artis‘a species are found with the characters of the 
Conifers, the Artisia of Cordaites, or those described by the authors and 
referred to plants of different genera, should have the same characters. 
This has not been positively established. 
Grand’ Eury refers Dadoxylom and its Artisia stem to Vordmites. Corda 
