Holden. — fur as sic Coniferous Woods from Yorkshire. 535 
they appear as white lines between the pits. It is this feature which has 
been used in the following descriptions to differentiate between Araucarian 
and Abietineous woods. 
Araucarineae. 
Xenoxylon phyllocladoides , Gothan (PI. XXXIX, Figs. 1-4). 
Wood of this type composed the greater part of the lignite from 
Scarborough, and is, as a whole, in a perfect state of preservation. Its general 
character may be observed in Fig. 1 ; the annual rings are well marked, 
with but a small amount of summer wood, there is an abundance of ray 
parenchyma, but no wood parenchyma. The nature of the rays is shown in 
Fig. 2, or better, in the more highly magnified view of Fig. 4. The hori- 
zontal and end walls are thin and unpitted, while on the vertical wall 
communicating with the tracheides there are large ‘ Eiporen \ Usually 
there is but one, rarely two, to each cross-field. The character of the 
tracheary pitting is evident from Figs. 2 and 3. The pits are large, usually 
remote (though rarely compressed and flattened), and, instead of being 
circular, are elongated in a horizontal direction. When in more than 
a single row, they are usually opposite, but sometimes alternate. In Fig. 3 
a dark spot may be seen in the centre of the mouth of each pit. In radial 
section it looks like a small torus, but tangential sections show that this 
appearance is due to a particle of dirt having become lodged there. The 
exceedingly large ‘ Eiporen * indicate that this wood is a species of Xenoxylon 
and the character of the tracheary pitting exactly resembles Xenoxylon 
phyllocladoides , Gothan. The only difference between the two consists in 
the shape of the ray. According to Gothan, the rays of Xenoxylon phyllo- 
cladoides are much higher than wide, so that in tangential section they 
appear oval. Such is distinctly not the case here. Figs. 1 and 2, both 
photographed at the same magnification, show them to be of approximately 
the same dimensions in the two planes, and their circular outline in tangential 
section proves the point. This wood seems also to be identical with Cu- 
pressinoxylon Barberi , Seward, from the Jurassic of Whitby, though lacking 
the resiniferous tracheides of that specimen. In regard to the affinities of 
Xenoxylon phyllocladoides , Gothan (2, p. 38) states that it is ‘ without 
analogy in living or fossil gymnospermous woods \ The absence of bars of 
Sanio, however, shows that it belongs among the Araucarian Conifers, 
a conclusion borne out by the occasional compressed and flattened condition 
of the pits, though among living Araucarian forms there are none with 
similar pitting of the rays. 
Locality: Scarborough. Horizon: Oolite. 
