208 
Ruth Holden. 
the fossil under consideration, where they fill the lumen of almost 
every tracheide. In addition to tyloses and trabeculae, there is a 
third variety of cross partition—the so-called “ resin spools.” 
These are very characteristic of the Araucarineae, both living and 
fossil; see Thomson (19), Lignier (10) and Jeffrey (9). 
We come now to the affinities of this fossil, and the extra¬ 
ordinary development of tyloses recalls immediately Protocedroxy- 
lon araucarioides, described by Gothan from the Upper Jurassic of 
Spitzbergen (4). Not only in this feature is the resemblance close, 
but also in the combination of Araucarian pitting of the tracheides 
and Abietineous pitting of the rays. Specimens of the same 
structure were found by the writer (8) in the Lias of Scarborough 
(Yorkshire) and described as Metacedroxylon araucarioides, the 
generic name being changed to avoid an implication of Abietineous 
affinities. In two respects, however, this wood differs from the 
Yorkshire and Spitzbergen specimens—the lack of tangential 
pitting, and the frequently biseriate character of the rays. Although 
these may seem relatively unimportant points, recent investigations 
of living conifers indicate that both are remarkably constant. For 
example, tangential pits are uniformly absent in hard pines, but are 
abundant in the summer tracheides of soft pines and of the remain¬ 
ing genera of the Abietineous series, while in the Taxodineae and 
Cupressineae they may occur scattered throughout the year’s growth. 
As regards rays, these are typically uniseriate in the Coniferales as 
a whole, but in Sequoia sempervirens biseriate ones occur even more 
frequently than in the case of this fossil. It seems best, accordingly, 
to institute a new species for this specimen, and to denote its 
source, it may be called Metacedroxylon scoticum. 
Summary. 
From the Corallian of Loth, there has been described a 
coniferous wood, characterised by a combination of Araucarian 
pitting of the tracheides and Abietineous pitting of the rays, and by 
a remarkable abundance of tyloses in the tracheides. For this 
specimen the name of Metacedroxylon scoticum is proposed. It differs 
from Metacedroxylon araucarioides (Protocedroxylon araucarioides 
Gothan) only in the absence of pits on the tangential walls of the 
tracheides, and in the biseriate character of the rays, and it confirms 
the conclusion of Dr. Stopes that the plants of the Scottish Oolites 
belong to the same “ life province ” as that which included Yorkshire 
—to which we may add Spitzbergen—during that period. 
Botany School, 
Cambridge, April, 1915. 
