438 
“ About a mile s. of a little country town called Kesick [Keswick], 
and near two furlongs from Hartford [Harford] Bridge, is a pit in 
whicli the country people dig a particular sort of clay— to lay upon 
the sandy lands. Amongst this clay are a great many knots, lumps, 
or nodules of a blue sort of earth, not widely differing from that 
which is found in Harwich cliff : these when digged up are soft, 
hut when they have been for some time exposed to the open air, 
they become almost as hard as flint. In and upon these lumps are 
the impressions of the Cornu Ammonis or snake stones in a beau- 
tiful manner, from an inch to five inches in diameter, and several I 
saw with part of the shells upon them of a yellowish white. 
“ Many other shells are to be found in these lumps, as the pectun- 
culus, helmet stones, belemnites, common cockle, turbos, &c., but 
they are most of them very small. 
“But still more curious than all are certain lumps of petrified, 
crystallized matter of a very odd form, such as I have never seen 
or read of. They appear to have been originally lumps of blue 
clay, cracked by some subterranean heat or other unknown cause, 
into which the water had insinuated, and the salts contained in 
them have crystallized in the cracks. When these lumps are taken 
up and become dry, the clay part falls from the external cells, and 
then they may be thought grossly to represent an Honeycomb. At 
first I took them to be bones from withinside the skull of some 
great fish or other sea animal, but some I have seen lately, and of 
which I shall send you a specimen, have convinced me I am mis- 
taken ; indeed, since I wrote the above, I have compared this fossil 
with the description Dr. Woodward gives of the Ludus Helmontii, 
and I think it agrees somewhat therewith.” 
The origin of fossil shells, &c., seems to have puzzled the 
philosophers of that period, and various theories were started to 
account for their presence in the rocks. “ The ever-memorable Dr. 
Hook ” says that earthquakes seem to be the chief efficients which 
have transported these petrified bodies, shells, wood, Ac., and left 
them in such parts of the earth as are not otherwise likely to have 
been the places wherein such substances should be produced. 
With this opinion Mr. Arderon is not disposed to agree : the regu- 
larity of the strata of shells, lie thinks, confutes this theory. 
“Dr. Woodward’s hypothesis, or manner of bringing these shells 
and all other forms into the places where we now find them, by a 
