BEIvrSTEAD — OH" THE GEOLOGY OF MAIDSTONE. 
339 
Museum. Your tooth belongs to the species continues, so called on 
account of the enamel being continued from top to bottom ; the den- 
tine is compact, and has been resolved by decomposition into a series 
of superimposed hollow cones ; the pulp-cavity is confined to the base 
of the crown, by which it differs from the teeth of the Hypsodon." 
A paper was read before the Geological Society on the pecuUarity 
observed in this layer, of the cavities of the shells being filled witli 
molluskite. In the blocks of " firestone " or Upper Greensand, which 
are visible at low-water along the shore at Southbourne, Sussex, small 
concretions of phosphate of lime are thickly interspersed amongst 
the fossil shells. In my earliest geological researches along tlie 
Sussex coast, these fossil bodies particularly arrested my attention ; 
but I failed to obtain any clue to their origin until the important 
memoir on coprolites, by Dr. Buckland, pointed out the right path 
of inquiry, and gave the clue to the formation of molluskite from the 
animal matter of the shell-fish. 
That a large proportion of these phosphatic concretions and nodu- 
lar masses are the mineralized egesta of fishes and other marine ani- 
mals, there can be but little doubt, although it is rarely, if ever, possible 
to detect any traces of the convolutionary form of the intestines 
through which they have passed, and which are always more or less 
strongly impressed on the coprolites of the Chalk, Wealden and Lias. 
In the Southbourne rocks, however, instances are very common in 
which the phosphatic matter occurs as casts of shells, especially of 
the genera Venus and Trochus, which abound in the firestone beds ; 
the substance of which casts appears, therefore, to have originated 
from the soft bodies of the mollusca that died within them. In 
Sussex, these phosphatic nodules are very abundant in the layers 
of the firestone which form the junction with the Gault. They are 
also frequent in the beds of Gault at Eingmer and Nortington, near 
Lewes, and in the Surrey strata. They also occur at Folkestone, in 
Kent. At page 296, 1 also mentioned the occurrence of similar nodules 
at New Hythe. The late Dr. Fitton, in his elaborate memoir ' On 
the Strata below the Chalk ' (Trans. Geol. Soc. vol. iv. pi. 2, p. Ill), 
has given a description and analysis of those coprolitic nodules and 
concretions which occur at Folkestone. He says, " They resemble 
coprolites in their chemical composition, though no traces of animal 
structure are apparent in them. They sometimes enclose portions of 
shells, but no fragments of bones or scales of fishes.* In some cases 
they are of very irregular figure, surrounding or incorporated with 
fossil remains, the interior of which is filled with matter of the same 
* In some few cases I have found fish scales and small teeth of sharks in those at 
Folkestone. Shell-casts, especially of Dentalia, are very common ; and one very important 
layer in the Gault at Tolkcstone is entirely formed of the more or less broken casts of 
ammonites. Portions of wood are extremely common in the nodules forming the junction 
bed of Gault and Lower Greensand there. Fossil oyster-shells and serpula are very com- 
monly attached to their exterior surfaces, showing they were consolidated whilst lying 
at the bottom of the Gault and Greensand seas, and before they were embedded. — 
Ed. Geol. 
