BENSTED — OS THE GEOLOGY OF MAIDSTONE. 
337 
a portion of a small stem, eight inches long, which is converted into 
black flint, to the extent of six or seven inches, while the remainder 
is a friable carbonate of lime ; the general aspect of this specimen, 
and the indications of eight irregular branches, prove at once its 
exogenous character. The cone found associated with this wood is 
in every respect such a fruit as a tree of the kind above described 
would produce. It bears a close resemblance to a fossil from the 
Greensand of Dorsetshire, discovered by Dr. Buckland, and figured 
in the 'Fossil Flora of Great Britain' under the name of Abies oh- 
longata. In its general form, and in the shape of the scales and seeds, 
the Maidstone specimen is decidedly distinct. Unfortunately, the 
outer surface is so much worn that the external figure of the scales 
cannot be accurately defined, but the sections show their propor- 
tionate thickness ; and as Abies is distinguished from Pinus by the 
thinness of the ends of the scales, the affinity of the fossil is clearly 
ointed out. There is an opening at the base of the cone occasioned 
y the removal of the stalk (PL xix. fig. 1), and an accidental oblique 
fracture exhibits the internal structure. In the longitudinal section 
thus exposed (fig. 2), the scales are seen to be rounded and broad 
at their base, and to rise gradually and become thin at their outer 
terminations (fig. 3). The seeds are oblong, and one seed is embedded 
within the base of each scale ; in some instances there appears to be 
the remains of the embryo." There are about twenty-three seeds 
observable in the sections!^ 
This limestone group is followed by a series of chert beds or sili- 
ceous hassock. The chert is nearly black, and in places very shat- 
tery ; the more solid parts are very hard. An interesting occurrence 
took place a few years since, which elucidates in one way how flint 
veins in the chalk may be shattered in situ, as they are seen to be in 
some localities in the Isle of Wight. The stone is thrown down in 
my quarry in immense quantities, and in the fall of a large mass 
of some hundreds of tons the concussion so acted upon the brittle 
texture of the chert-seams as to shiver them into thin fragments, 
while the limestone with which they were intercalated in the block 
was scarcely at all aftected. 
The next group of strata, which, from the occurrence in it of the 
bones of that reptile, I have called the Iguanodon group, consists of 
two thin layers of very light-coloured limestone with intercalated 
seams of hassock, much of the loose and " shaky" portions of which 
consist of stems and nodules similar to the Spongites Benstedii. 
Hitherto very few shells have been met with, but in this group we 
find the first distribution of a very characteristic one, Trigonia alce- 
formis. A Trigonia, but of another species, T. spinosa, occurs in the 
upper bed of irregular ferruginous stone ; the specimens of which are 
usually converted into chalcedony having the lines upon the shells 
clearly defined, but in these Iguanodon beds casts only are met with, 
a residue of white powder being all that remains of the shells ; it is 
thus very rarely that the fossils can be extracted from the stone, 
little more than the impressions in most cases remaining. 
