[PENHALLOwW] CRETACEOUS AND TERTIARY PLANTS OF CANADA 48 
GINKGO PUSILLA, Dn. 
(Plate XII. and Plate XIII. fig. 1.) 
Dawson, Trans. R. Soc. Can., VI., iv. (1888), 72; XI. (1893), 56 & 73 (foot-note). 
Upper Cretaceous of Port McNeil, Vancouver Island, and U.C. of Cumshava 
Inlet, Q.C.I. 
Hitherto this species has been known only through its foliage as 
described by Sir William Dawson in 1893," but in the material collected 
at Cumshava Inlet, Queen Charlotte Islands, there was a fragment 
of a branch which was readily recognized as a Ginkgo. The specimen 
measured 5-5 em. long, and it had been compressed into a narrowly 
elliptical transverse section 2 cm. wide and 3-5 cm. long. No external 
evidence of bark could be found, but there were indications of more 
or less extended decay which had resulted in leaving somewhat 
irregular surface depressions and concavities from which angular 
fragments had been removed. The section shows a portion of the 
pith and medullary sheath in a very fair state of preservation. The 
wood has been subjected to somewhat advanced decay, so that areas 
show no structure whatever. When the wood structure is preserved, 
as it is through the greater part of the stem, it is in such condition 
as to permit a recognition of all the essential details. Growth rings 
are obvious, but the sharpness of their definition has been obscured 
by the action of decay which has reduced the thickness of the walls 
in the summer wood so that the cells cannot be readily differentiated 
from those of the spring wood. ‘The whole structure is calcified. 
The following are the structural details observed: 
Transverse. (Fig. 11). Growth rings obvious, the spring wood 
passing gradually into the not strongly defined summer wood; medul- 
lary rays very narrow; tracheids in regular radial rows, very uniform, 
those of the spring wood about 22 X 21 u the walls 5-3 x thick. 
Radial. (Fig. 12). Medullary rays very low, the cells straight, 
about 17 y high, equal to about 5 tracheids; the upper and lower 
walls thin and not pitted; the terminal walls thin, straight and devoid 
of pits; the lateral walls with large? pits, one per tracheid. Bordered 
pits on the radial walls of the tracheids not recognizable. 
Tangential. (Fig. 13). Medullary rays 1-3, more rarely 4 cells 
high, about 8-7 / broad. 
The fact that Ginkgo pusilla is the only species so far reported 
from this locality, appears to justify reference of our present material 


1 Trans. R. Soc. Can., XI., iv., 56. 
