480 



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 

 affinities with the Lycopodiacem^ and especially with the genus Psi- 



