NEWBOLD ON THE SILICIFIED WOOD OF EGYPT. 357 
lst. That this part of Egypt has twice formed a portion of the 
ocean’s bed, elevated at distinct periods above its surface. 
2nd. That the fossil trees existed in a vegetating state between 
these two epochs, or after the first appearance above the ocean of the 
marine limestone,—were submerged or carried into the sea—covered 
with a bed of rolled pebbles and sand, and raised with this bed to 
their present position above the general drainage-level of the country 
and the reach of existing springs. 
The consolidation of the ocean’s bed and silicification of the trees 
probably went on together prior to, or perhaps contemporaneous with, 
the soulévement. 
3rd. That the elevation of these beds was attended with no violent 
disturbing cause, but effected gently and gradually, as appears from 
their nearly horizontal position. 
4th. That it is probable that the retiring waters of the last ocean 
swept away the looser portions of this and other once continuous beds 
of sandstone,—denuding in places the subjacent limestone, scatter- 
ing the debris of pebbles, sand and fragments of silicified wood over 
a vast extent, and forming the present gravel and saline sands that 
cover the surfaces of the Egyptian and Libyan deserts. 
5th. From what has been already stated respecting the manner in 
which some of the fossil stems near Cairo have been broken,—their 
little-worn aspect,—the angularity and nice adaptation of many of the 
fractured portions, it is reasonable to infer, in that locality at least, 
that they rest at no great distance from the spot on which they were 
silicified. From the fact of the vertical position of a few of the trunks, 
it might be still further presumed they are now seen where they ori- 
ginally vegetated; but until these vertical stems be traced down to 
roots fixed in a given stratum or on certain levels, marking, like the 
Portland dirt-bed, the ancient surface of dry land (facts which it is 
extremely desirable to ascertam or disprove), we must hesitate to 
admit the hypothesis of the Cairo petrifaction-bed being the site of a 
submerged forest. 
VOL. IV.—PART I. | | 2p 
