Preliminary Report on Specimens of Silicified 
Wood collected by John Muir, Esq., at 
Adamana, near Holbrook, Arizona, U.S.A. 
BY 
W. T. GORDON, M.A., B.Sc., 
FALCONER FELLOW, EDINBURGH UNIVERSITY. 
Twelve specimens! of fossil wood were sent for examination, 
and of these, three were not sufficiently well preserved for 
identification. Two of these three had patches of the tissue 
preserved, but the third specimen had no structure. The 
remaining nine were all specimens of Avraucarioxylon, and one 
of them is a new species; on this last, more research is necessary 
before a complete description can be given. An interesting 
point brought out by this collection is that the darkest and 
dullest specimens shew more perfect preservation of the tissues 
than the clearer and brighter ones. It is to be hoped that 
Mr. Muir may be able to obtain further examples of wood from 
this locality, and that cones belonging to these trees may also 
be discovered. The following is a list (with short descriptions) 
of the specimens :— 
No. 1. Stem with tissue preserved only in patches. 
No, 2. Thin fragment of wood near the outside of the trunk. 
The branch bundles have a quincuncial arrangement. 
The cells have bordered pits on their radial walls, and 
the medullary rays are from 2 to 10 cells high. 
No. 3. A new species of Araucarioxylon with broad medullary 
plates separating the xylem plates. Small normal 
medullary rays traverse the xylem plates. The cells of 
the medullary plates are elongated transversely, and 
1 The Royzl Botanic Garden is indebted to Mr. David Douglas, 10 Castle Street, 
for these specimens which were received in 1907.—/. B.A. 
[Notes, R.B.G., Edin., No. XX, March 1909. | 
