[PENHALLOW] NORTH AMERICAN SPECIES OF DADOXYLON 67 
They also show bordered pits in section. One tangential section shows 
very clearly, either a resin canal or a series of resin cells—probably the 
latter. From these data the following diagnosis may be obtained :— 
Transverse—Growth rings obscure or entirely wanting. The tracheids about 
41 x 49 mic. broad, their walls 12.5 mic. thick. 
Radial.—Bordered pits numerous throughout the tracheids, in 2-3, more rarely 
in 4 rows. The elements of the medullary rays of two kinds; the 
parenchyma cells thin-walled and devoid of pits, about equal to 3 
tracheids; the ray tracheids long, interspersed and bearing on their 
lateral, upper and lower walls, numerous crowded, bordered pits. 
Tangential.—Rays very variable, commonly 1-seriate but sometimes 2 seriate 
in part; the tracheids usually distinguished by their narrow form 
and pitted walls. 
CORDAITES OUANGONDIANUM, Dn. 
Bib. :—Proc. U. S. Nat. Mus., XII., 606; Brit. Mus., 1886, 237; Géppert, Nachtr. 
z. Kennt. d. Conif. d. Pal. Form., 1888, 9; Can. Nat., VI., 165; Jn’l Geol. 
Soc., XVIII., 306; Acad. Geol., 3d ed., 1878, 534; Dana, Man. Geol., 
1875, 271; Pre-Carb. F1. of N. B., Maine and E. Can., Can. Nat., 1861, 
VI., 165-166; Quart. Jn’l Geol. Soc., 1862, 306; Zittell, Schimper & 
Schenk, Handb. der Pal., 1890, 865; Foss. Pl. of the Dev. & U. Sil. 
in Can., 1871, 12. 
Dist.—Middle Devonian of New Brunswick. 
The original description of this species, which has been copied by 
subsequent authorities without question or verification, was contained in 
the account of the Pre-Carboniferous flora of New Brunswick, Maine 
and Eastern Canada published in 1861.1. In the light of more recent 
studies, this description is found to contain several marked errors which 
probably resulted from the nature of the material employed. Our own 
studies show that the transverse section displays no essential divergence 
from the characters common to the genus as a whole. There is no 
evidence of growth rings such as form a prominent feature of the orig- 
inal description. At intervals in the section, the structure which has 
been greatly influenced by decay, has been so far altered by pressure as 
to form irregular lines of compressed tracheids which have been forced 
over to one side in the process, as is not uncommon in fossil woods. 
There has thus been developed a semblance of growth rings, and this is 
what the original description refers to. A critical examination of these 
areas, however, does not fail to disclose the true condition which is also 
suggested by the very irregular disposition, as also by other features pre- 
sented. 
1 Can. Nat., VI, 165-166. 

