342 St opes. — A Neiv Araucarioxylon from New Zealand. 
by a thick bark, as is seen in PL XX, Photo i. This deceptive appearance 
depends on a peculiarity of petrifaction', the central region, of darker and 
denser structure, is about 3-4 cm. in diameter, and rather irregular in out- 
Text-fig. i. Transverse section of part of the wood, showing the sharp alternation between 
spring and autumn wood, a , a , limits of annual rings, m, medullary rays, bordered by special thick- 
walled tracheides r.t. e shows one of these with thick wall, but empty of resin ; x shows some with 
thick walls and resin deposit round them. 
line ; its boundary bears no relation to the limits of the annual rings, but 
cuts sharply across them, as can clearly be seen in Photo 1, s ; the outer 
zones of the fossil, as at c , are also composed of petrified rings of secondary 
