File:The Quarterly journal of the Geological Society of London (12981038425).jpg

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PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
.Jan. 5,
maria, but irregularly disposed, and giving origin to the roots, which,
however, unlike those of Stigmaria, subdivide in descending into the
soil. Apart from the stems, these rhizomata might be included in
the genus Karstenia or Halonia, or even as abnormal species in
Stigmaria (figs. 1 a,g). The aerial stems vary from a fourth to a
tenth of an inch in diameter at their origin, rise obliquely from the
rhizoma, and bifurcate very regularly. The extreme points divide
nearly at right angles, and in some, probably young, branches the
ultimate branchlets bend into a spiral curve with a somewhat uni-
lateral arrangement of the leaflets. In the shale overlying the small
coal-seam above-mentioned, there are immense numbers of these little
branchlets, rolled so closely as to resemble spiral shells. They probably
indicate a circinate vernation like that of ferns. (See figs. 1 &, c, d.)
The surface of the stems is very smooth and glossy, quite destitute
of scars, but marked vdth numerous interrupted ridges spirally
arranged, and sometimes seen to project a little at the upper ends, as
if rudimentary leaves. This leaf-like character is more distinct
towards the extremities of the branches ; but the leaves are not
sufficiently weU preserved to show anything more than that they are
slender and acicular. (Figs. 1 c,f,7i, p. 479.)
The greater part of the specimens are flattened, with the epidermis
alone preserved in a coaly state ; but a few fragments were found
Fig. 1 k.
Fig. 1 1.
Fig. 1 k, longitudinal section of stem, nat. size ; I, cortical cells (300 diams.) ;
m, parenchyma (300 diams.) ; n, scalariform tissue of axis (300 diams.).
with the internal structure remaining. It consists of a slender axis
of scalariform vessels, surrounded by a space now occupied by calc-
spar, but showing in parts the remains of a loose cellular tissue.
Externally to this is a cylinder of weU-preserved, elongated, woody
cells, without distinguishable pores, but with traces of very delicate
spiral fibres. (Figs. 1 k, I, m, n.)
The structure and external appearance above described indicate