536 Holden. — Jttrassic Coniferous Woods from Yorkshire . 
Xenoxylon latiporosum , Gothan (Figs. 5 and 6). 
Sections of this type were cut from a block of petrified wood found on 
the Yorkshire coast, a short distance north of Robin Hood’s Bay. Fig. 5 
shows a typical radial section. Like Xenoxylon phyllocladoides , the wood 
consists entirely of tracheides and rays, and the rays have one large pit 
which covers the entire cross-field. Unlike the former, the tracheary pits 
are invariably flattened and closely compressed. The extreme compression 
has resulted in the appearance of pits which are fully twice as wide as high 
(Fig. 6). When two-ranked, the pits are always alternating (Fig. 6). In 
every respect this specimen is identical with Xenoxylon latiporosum , 
Gothan, and must be included among the Araucarineae, both on account of 
the absence of bars of Sanio and the presence of alternating pitting. 
Locality : Robin Hood’s Bay. Horizon : Lias. 
P araphyllocladoxylon eboracense (Figs. 7- 9). 
Figs. 7-9 show the character of this lignite. The radial pits of the 
tracheides are usually scattered and circular (Fig. 7), but are never separated 
by cellulose bars of Sanio. Tangential pitting is abundant (Fig. 9). The 
rays are smooth-walled, with one, rarely two, large pits to each cross-field 
(Fig. 8). These pits are, however, conspicuously smaller than those of 
Xenoxylon (cf. Fig. 4). In Fig. 9 several of the tracheides have dark cross- 
walls which give the appearance of wood parenchyma. The character 
of the partition shows that it is a resin plate, due to the fact that certain 
tracheides become filled with resin. That this resinous substance is derived 
from the rays is shown by the dark content of one tracheide in the centre 
of the field, which lies immediately next the ray. Jeffrey (7, p. 538) has 
referred to similar resinous exudations in the wood of living and fossil 
Araucarians, and suggested that this is the explanation of the apparently 
thick- walled tracheides situated next the rays in some of Lignier’s specimens. 
This wood closely resembles the Phyllocladoxylon described by Gothan 
from King Karl’s Land. It would seem better, however, to reserve the 
generic name Phyllocladoxylon for podocarpineous forms with these large 
4 Eiporen ’, and to use the name P araphyllocladoxylon for similarly charac- 
terized Araucarians. Since this specimen is from Yorkshire, it is proposed 
to call it P araphyllocladoxylon eboracense. 
Locality : Scarborough. Horizon : Oolite. 
P araphyllocladoxylon araucarioides (Fig. 10). 
This material was among the specimens sent by Mr. Lomax to 
Professor Jeffrey. As shown in Fig. 10 the rays closely resemble those 
of the last-described wood. The tracheary pits, on the other hand, are 
