20 
Mr. W. Pengelly on the Bed Sandstones, 
Beekite are frequently seen in the Greensand fossil shells of Haldon ; 
in this case, however, the fossils are entirely silicified, not merely 
coated with chalcedony as in the Torbay specimens. My friend, Mr. 
C. W. Peach, some time since, sent me a small specimen which he had 
found in the north of Scotland. The facts that one penny stamp paid 
its postage, and that Mr. Peach requested it might be returned to 
him, will serve to show both the small size and the rarity of Beekites 
in that region. Mr. A. Williams has also sent me a small specimen 
from the mountain Limestone of the Mendip hills. So far as I have 
seen, the Beekite is invariably formed on a calcareous fossil nucleus. 
But to return. Since, as has been stated, the nuclei are calcareous 
and contain Devonian fossils, they are, undoubtedly, portions of the 
adjacent Devonian limestone ; and, as the Conglomerates must be 
regarded as ancient sea-beaches, these limestone fragments must have 
been pebbles on those beaches ; and, consequently, they must have 
been rolled and abraded as pebbles necessarily are under such cir- 
cumstances. Now had they then possessed their crusts of chalcedony 
these would have been scratched and worn as in the case of the 
Beekites which have been rolled on the modern beach ; but it has 
already been stated that they are in all cases quite free from marks 
of this nature, hence it seems safe to conclude that the chalcedony 
has been deposited on them since the cementation of the Triassic 
Conglomerate. 
Though the nuclei are sometimes more or less silicified, the fact 
that they are frequently — more frequently than otherwise — purely 
calcareous proves that this character cannot be regarded as an essen- 
tial character of the Beekite ; hence the formation of the crust of 
chalcedony does not depend on the silicification of the nucleus, 
though probably the latter may have resulted — at least in some cases 
— ^from a continuation of the process by which the former was 
efiected. 
From a consideration of all the facts of the case, it seems probable 
that, after the formation of the Conglomerates, water, holding car- 
bonic acid and silex in solution, percolated through the rock, that the 
acid dissolved, and the water removed, the carbonate of lime of 
which the pebbles consisted, and that the silex replaced the calcareous 
matter. Notwithstanding its being completely invested with chalce- 
dony the nucleus appears in some cases to have continued very slowly 
to decompose but not to be silicified, in others no change followed 
the formation of the crust, whilst in a few instances the entire mass 
was more or less replaced by chalcedony. 
The fossilization of organic remains is confessedly not well under- 
stood, but it does seem possible that the chalcedonizing process might, 
in some cases, extend through the crust already formed to the nucleus 
within, or to portions of it ; or, since we frequently find that organic 
remains in ordinary limestone rocks are more or less siliceous, as 
