250 Notice of a Stlicious Petrifaction. 
properly with lime, &e. that a valuable and cheap water™ 
proof mortar might be obtained. 
N. B. The specimen of petrified wood is about eight- 
een inches by six inches. It is entirely silicions, a part of 
it resembling the coarser varieties of wood opal, generally 
opaque white, but in some portions stained of a rust or vio- 
let colour by oxide of iron. The wood is unquestionably 
pine. The layers and fibres are distinctly preserved. There 
is a knot, very exactly imitated, and on the outside of this 
: rthere is a colleetion of resinous matter, such as-is com- 
. “ 
binant 
Pave. 
mon HY similar ions in decayed trees now standing. 
belonged to a dry tree, from which the bark had fallen, and 
its surface exactly resembles the half decayed surface of dri- 
ed trees, It is worm eaten, and the intervals between the 
outer layers are filled with the dust deposited by the larveot 
insects. ‘Though most of the specimen, particularly the 
firmer parts, is flinty or opaline, (there is a clear line of sep- 
aration between the opaque white and senti-translucent vio- 
let coloured portions of which it is chiefly composed,) yet 
the open spaces between the layers, and particularly around 
the knot, are lined with minute quartz crystals. The s 
cimen is said to have been taken from an entire tree, which 
lately stood erect and imbedded in a hillock of loose sand. 
It probably grew on the spot, and was killed and gradually 
covered by the blowing sand. The specimen of the rock 
18 a sand stone cemented by oxid of iron, formed of the com- 
mon coarse sand of the southern pine forests. Such sand 
stones are common all over the Southern states, from N- 
Jersey to Alabama, particularly near the borders of the 
primitive. They form entire hillocks in the barrens oppo- 
site Philadelphia, where they have a striking resemblance 
to sand hardened by frost. J. GP.) 
