72 | ROYAL SOCIETY OF CANADA 
collection from Prof. Prosser, as derived from the Chase formation 
(Permian) of Chase County, Kansas. 
Transverse.—Tracheids 47 x 47 mic. broad, the walls 9.3 mic. thick. 
Radial.—Ray cells straight or abruptly narrowed at the ends, equal to 3-4 
tracheids; the lateral walls show no recognisable structure. 
Bordered pits in 1-3, chiefly 2 rows, hexagonal, 12.5 mic. broad. 
Tangential.—Rays numerous, 1-seriate or 2-seriate in part, the broadly oval, 
thin-walled cells 28 mic. broad. 
CORDAITES HAMILTONENSE, n. Sp. 
Figs. 2-7. 
An undescribed species from the Genesee shales (Hamilton Group) 
of Ontario Co., N.Y. Collected by Prof. J. M. Clarke. Material in the 
collection of Sir William Dawson. 
This specimen shows many interesting details of bark structure, 
which serve to enlarge our knowledge of the general structure of these 
plants. For the purposes of this description, and as represented by the 
fossil, but without strict reference to the proper subdivisions of that 
structure, the bark may be divided into three zones, the inner, middle 
and outer. In a transverse section the following details appear :— 
The inner zone (fig. 2) is composed of isodiametric, thin-walled 
parenchyma elements. Scattered through this region, but chiefly form- 
ing a limiting layer on the outer face, there are numerous resin bearing 
elements which in the latter situation assume much greater dimensions, 
but the details of structure of which cannot be satisfactorily determined 
owing to the alteration of parts. The middle zone (fig. 3) consists of 
radially elongated, thin-walled elements which simulate cork in their 
tendency to disposition in radial series. Its radial extent is about equal 
to or somewhat in.excess of the inner zone. Throughout its entire 
extent, resin canals of simple structure and of variable size, are distri- 
buted in large numbers, and in some cases at least, they appear to be 
derived from the main system of canals forming the outer limit of the 
first, and the inner limits of the second zone. The outer bark is repre- 
sented by a broad zone of structure in process of disintegration. This 
is shown in part in fig. 4, which also includes the outer part of the 
middle zone. 
The outer bark is represented by a broad zone of structure in pro- 
cess of disintegration. This is shown in part in fig. 4, which also in- 
cludes the outer part of the middle zone. 

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