48 ROYAL SOCIETY OF CANADA 



but it does often happen that Pseudotsuga presents precisely the 

 characters thus described, from which circumstances I feel justifiedl 

 in regarding the Taxoxylon in question as really Pseudotsuga miocena 

 with which it fully agrees. 



The specimens described in the first diagnosis^ were very poorly 

 preserved. The material from the Great Valley Group is in many 

 respects in a much better state of preservation, in consequence of which 

 it becomes possible to recast the diagnosis on the following lines: — 



Transverse. — Growth rings broad and prominent; the tracheids of the spring 

 wood large and thin-walled, the structure passing gradually into the 

 thin but rather prominent summer wood composed of about 3 — 10 

 rows of thick-walled tracheids. Resin cells not obvious. Resin 

 canals small, not very numerous, chiefly in the summer wood, often 

 double as in P. douglasii; the epithelium cells small and thick walled. 

 Medullary rays slightly resinous. The entire structure of the trans- 

 verse section bears a strong resemblance to the fine grained wood 

 of P. douglasii. 



/^arfio^— Bordered pits in one row. Cells of the medullary rays straight, the 

 thin upper and lower walls devoid of pits. Pits on the lateral walls 

 of the ray cells about 4 per tracheid. 



Tangential. — Ordinary rays uniseriate or 2-seriate in part, the cells oval or 

 round, thick walled, about 24.5 // broad. Fusiform rays narrow, the 

 cells thick-walled, the resin canal narrow. 



Ehamnacinium poecupinianum, n. sp. 



Figs, 14, 15, 16, 21, 22. 



Eocene of the Porcupine Creek and Great Valley Groups. 



Bib. : — Knowlton, Cat. Cret. & Tert. Flor., 199; Felix, Untersuchung uber fos- 

 sile Holzer; Zeitscher, d. Deutsch. geol. GeselL, 1896, 252, pi. VI., fig. 

 3; B. N. A. Bound. Comm., 1875, App. A, 330; U. S. Geol. Surv., Mon. 

 XXXII. Part II., 769, pi. CXVIII and CXIX; Trans. R. Soc. Can., IV., 

 iv., 27, etc. 



In his original examination of woods from the Great Valley Group, 

 Sir William Dawson recognized only one Angiospermous type. This 

 he regarded as referable to the genus Populus which is also largely 

 represented in the same beds by fossil leaves.' The specimen now 

 under consideration is identical with the Populus thus referred to, 

 but it requires further determination of its specific characters. The 

 determination as originally made was no doubt suggested by the very 

 striking resemblance which the structure of the transverse section 

 bears to the poplars, and especially to P. balsamifera, but a more 



' Trans. R. Soc. Can., VHI., iv., 68, 1902. 

 2 B. N. A. Bound. Comm., 1875, App. A, 331. 



