NER eee 
Rg a a a 
Ls a a li ea ie 
1912] THOMSON & ALLIN—PITYOXYLON 343 
traces in the radial and transverse sections of P. Chasense in rays 
which are quite similar in size and structure to those in the tangen- 
tial section (cf. plate figs. 6 and 7 with fig. 8), it is considered that 
these are identical with the fusiform rays described by PENHALLOW. 
In the radial section they pursue an almost horizontal course 
(plate figs. 2a [?] and 6), as is the case in the old wood of the 
Araucarineae. Further explanation need not be entered into here, 
since one of the writers is preparing a contribution to the character 
of the leaf trace in certain fossil and living conifers, in which this 
feature will be studied in detail. 
Since, then, the so-called resin canals of ‘‘ Pityoxylon Chasense”’ 
are proven not to be such, there is left no basis for calling this form 
a Pityoxylon. On the other hand, (1) the absence of annual rings, 
(2) the character of the ordinary medullary rays (1 to partly 2- 
seriate with cells of thin-walled unpitted parenchyma), and (3) 
the multiseriate, alternate, and hexagonal radial pitting of the 
tracheids afford clear indication of its cordaitean affinity. This 
form, then, instead of affording “full confirmation” (0p. cit., p. 1) of 
the authenticity of P. Conwenizianum, lends no support to it, but 
might rather be considered as emphasizing the insecurity of the 
evidence upon which, as GoTHAN has recently shown (see p. 1), 
the latter is referred to the Carboniferous. . The claim for the great 
geological age of the Abietineae thus fails on critical study of both 
the Permian and the Carboniferous forms upon which it is based. 
UNIVERSITY OF TORONTO 
LITERATURE CITED 
I. GoTHAN, W., Die fossilen Hélzer von me ORE: Kungl. Svensk. 
Vetensk. Akad. Handl. 42:no. 10. 190 
2. See fossilen Holzreste von Saiheebin Ibid. 45:no. 8. pp. 56. 
pls. 7 2 
a eet E. C., A fossil Sequoia from the Sierra Nevada. Bor. Gaz. 38: 
“ales pls. 18, Ig. 1904. 
, and Curyster, M. A., On Cretaceous Pityoxyla. Bort. Gaz. 
42:1-15. pls. 1, 2. 1906. 
5. PENHALLow, D. P., North American species of Dadoxylon. Trans. Roy. 
Soc. Canada. IT. 6: 51-97. pls. g. 1Q00. 
6. Scuimper and SCHENCK, Palécplyinieaie Part II of Zirret’s Traité de 
Paléontologie. Paris. 1891. 
