1 12 
St opes. — An Early Type of the 
because much comparative work on fossil wood is vitiated by ignorance 
concerning the age of the part described, or by comparisons of small twigs 
of fossils with trunks of living trees and vice versa. 
The growth rings are strongly marked and regular, thus supporting the 
geological deduction based on the single specimen Araucarioxylon Novae 
Zeetandii , Stopes, from the same district, that the seasons were well marked 
in the Upper (or Middle) Cretaceous 1 in the region now New Zealand 
(see Stopes, 1914 ). 
Before one can discuss the botanical significance of its features, and 
compare the new specimen with other fossils, it must be described in some 
detail. 
Description of the Specimen. 
General. The type and only specimen is a thick slab from a trunk not 
less than 30 cm. x 20 cm. in diameter, and probably more. The position of the 
pith is apparent, but five chalcedonized cracks centre upon it, so it is not 
clearly preserved. The greater part of the trunk is petrified in a close- 
textured, black matrix, largely silica ; the hard core in this case measuring 
17 cm. across. Round this are outer zones of less well-preserved woody tissue 
in bands of silicified and carbonate matrix mixed, the proportion of carbo- 
nate increasing towards the exterior. The appearance and peculiar mode 
of petrifaction is quite similar to the first fossil from this district which 
I described (see PI. XX, Fig. 1, Stopes, 1914 ). None of the outer tissues or 
bark appears to be preserved. 
Topography of the stem. The pith appears to be about 1 mm. in 
diameter, but is too broken for its details, or the details of the primary wood, 
to be described. 
The secondary wood shows very well marked growth rings which are 
clearly visible to the naked eye in the surface of the trunk which has been 
cut right across and partly polished. At least 130 rings can be counted 
in the polished surface, and as the microscopic sections reveal a larger 
number of rings per radial centimetre than are always apparent to the eye, 
it is likely that the tree was at least 150 years old, if not considerably 
more. The growth rings average 0-5 to 2 mm. in thickness, and there is 
a considerable proportion of thickened late wood in each growth ring (as 
can be seen in PI. IV, Fig. 1), which in most cases amounts to half or more 
than half of the wood of each ring. The rings consist on an average of about 
ten to thirty tracheides in each radial sequence. In a few places, lying in 
the radial series between the first spring tracheide and the last late-wood 
tracheide, are parenchyma cells with thickened and pitted walls. Resin 
canals and scattered parenchyma are absent. 
1 I he exact geological horizon cannot be determined by these two specimens, so for the horizon 
determination I depend on local geologists. 
