Pi 
NEWBOLD ON THE SILICIFIED WOOD OF EGYPT. 353 
traces of roots were found at this depth, but several loose masses 
imbedded in the sand bore strong resemblance to the bulbous base 
of palms; while others, again, assimilated to the tortuous structure 
of the roots of exogenous trees. No branches remained attached to 
any of the trunks that fell under my observation ; the places of their 
insertion were to be traced, and also knots; but in general the stems 
were straight, knotless, and with a longitudinally striated superficies. 
Some appear to have been in a state of decay at the time of their 
being imbedded, having a hollow interior partially filled up with grit 
and pudding-stone. A specimen from this locality, shown me by 
M. Linant at Cairo, had the hollow lined with a white caleedony-like 
siliceous substance full of small cells resembling those of a honey- 
comb. 
Many of the silicified trunks, both with regard to external and in- 
ternal structure, closely assimilate to the petrifactions found on the 
Coromandel coast near Pondicherry, and the imbedding rocks are 
similar m character and in their geognostic position. The respect- 
ive ages of the two subjacent marine limestones have not, however, 
been determined. Of the Egyptian limestone specimens have been 
already furnished. The hardness of the silicified wood varies from 
a whitish mealy opake crust, that crumbles between the finger and 
thumb, to that of translucent agate and flint; and in colour from 
white cornelian to red jasper, variegated with every shade of brown 
and grey. In some specimens all appearance of ligneous structure 
has been destroyed, the woody matter having been replaced by grains 
of sand agglutinated together, but preserving in a great degree the 
external form of the tree; like the fossil trees found at Dixon Fold, 
near Manchester, which are composed of the sandstone and shale of 
the coal-measures, and many other fossils of the coal-field sandstone 
of Europe. 
I was unable to detect decisively either the fruit-seeds or leaves of 
the fossil trees, but picked up one or two spherical ferruginous-lookmg 
nodules, from the size of a hazel-nut to that of an orange, which have 
been considered by many travellers, probably from shape merely, to 
be the petrified fruits of the date, doom-palm, and other trees. They 
resemble strongly similar substances which I found in the petrifac- 
tion-bed near Pondicherry just alluded to, and are usually composed 
of grains of quartz cemented by a mixture of ferruginous, siliceous, 
and argillaceous matter, sometimes hollow in the centre, like a geode, 
sometimes lined with minute drusy.crystals of quartz, but more 
frequently containing a yellowish or rust-coloured ochreous powder. 
The sandstone and fossil wood contain cells similarly lined. 
It must not be omitted to mention that in many of the fractured 
trunks, which he on the sand-hills broken transversely, the edges of 
the fractured portions are still sharp and in nice adaptation. Some 
lie several feet apart, like the fragments of a fallen column of marble 
separated by the heaviness of its fall, in such a manner as not to be 
explained by any theory of contraction or superincumbent pressure 
having occasioned their division. They appear to have fallen subse- 
quently to fossilization. After the consolidation of the lower beds of 
