18 



rows, but not contiguous. There are medullary rays which 

 are numerous, simple and of few tiers of cells superimposed. 

 The cortical tissues have perished. 



(b) The other stem is of smaller diameter with a strongly 

 marked Sternbergia pith, an inner layer of indistinct 

 pseudo-scalariform or spiral tissue and an outer layer, 

 much thicker in proportion, and with wood-cells having 

 three rows of contiguous hexagonal areoles with central 

 slit pores. The medullary rays are simple. This second 

 stem is not distinguishable from Dadoxylon of the type of 

 D. Brandlingii or D. materiariwn. The specimen itself 

 shows no evidence that it belongs to Cordaites. 



Setting aside, as probably Coniferous, the second specimen 

 and assuming the stem (a) to be truly Cordaitean, it 

 accords with one of the species of Dadoxylon described by 

 me from the Erian of New York, namely D. Clarkii, which 

 presents similar characters though with a somewhat thicker 

 woody cylinder. 1 D. Clarkii was described as follows in 

 1882. 



" The pith cylinder is large and shows ordinary cellular 

 tissue. The medullary sheath or inner fibrous layer consists 

 of pseudo-scalariform and reticulated fibres ; but the most 

 remarkable feature of this wood is the structure of the 

 medullary rays, which are very frequent, but short and 

 simple, sometimes having as few as four cells superimposed. 

 This is a character not before observed in coniferous trees 

 of so great age, and allies this Middle Erian form with 

 some Carboniferous woods which have been supposed to be- 

 long to Cordaites or Sigillaria." 



The resemblance of this peculiar stem to those of Cordaites 

 and Tylodendron, above referred to is obvious. 



I have noted and illustrated by characteristic examples, 

 the fact that the erect ribbed trees found in the coal forma- 

 tion section at the South Joggins in Nova Scotia, often con- 

 tain the remains of their axis, either calcified and standing 

 erect within the tree, or fallen to the bottom in the form of 

 mineral charcoal. The examination of a large number of 



1 Report on Erian Plants of Canada, Part II, 1882. 



