98 ROYAL SOCIETY OF CANADA 
form, low to medium; the cells very unequal and variable, chiefly 
rather thin-walled. 
Material strongly silicified, and the structure much altered by 
decay. 
So far as I am aware, there is no previous record of the occur- 
rence of this wood in any of the formations, and ait is therefore to be 
regarded as a wholly new element of the Tertiary flora. 
LAURINOXYLON BRANNERI, Knowlton. 
Figs. 6-8. 
Transverse.—Growth rings not recognizable in a radial extent of 1.8 cm. Wood 
cells rather small, very unequal and variable, but chiefly hexagonal, 
and in more or less distinct, radial rows; the walls rather thick, 
3.51, 4 but in most cases reduced to the primary wall by decay 
Medullary rays prominent, 1-3 cells broad, distant upwards of 7 rows 
, of wood cells. Vessels rather numerous, round and chiefly simple, 
but quickly becoming larger, radially oval and 2-seriate, and finally 
upwards of 4-seriate; resinous; at length abruptly reduced and 
simple, thus presenting a somewhat sharp contrast which is probably 
to be regarded as the junction of the two growth rings not otherwise 
recognizable. Wood parenchyma prominent, composed of large and 
thin-walled cells, forming conspicuous and often extended tracts about 
the vessels. 
Radial.—Ray cells of two kinds: (1), thin-walled, low, fusiform and equal to 
about 5 wood cells; (2), the marginal cells equal to about two wood 
cells, 1% times higher than long; the structure of the pits in all the 
cells obliterated. Vessels resinous, not obviously occupied by thy- 
loses, the radial walls with crowded, hexagonal pits. Wood paren- 
chyma prominent, the cells all thin-walled, short cylindrical, upwards 
of 5 times longer than broad, often showing nuclei. 
Tangential_—Medullary rays numerous, low to medium, 1-3 seriate, fusiform; 
the cells rounded hexagonal, but variable and unequal, thin-walled, 
those of the extremities often much larger. The rays commonly 
penetrate tracts of wood parenchyma. 
Material strongly silicified; in some cases well preserved, but 
usually showing the effects of advanced decay. 
The genus Laurinoxylon is very sparingly known through its wood. 
The first record of this species was made by Prof. Knowlton (11) in 
1889, based upon material derived from the Orange Sand gravels of 
Bolivar Creek, Poinsett County, Arkansas, which are of Eocene Tertiary 
age. The specimens studied were all silicified and apparently not 
very well preserved. The present diagnosis has been drawn from 
our own specimens, some of which, as the photographs show, are fairly 
well preserved. 
