On the Phosj)horic Strata of the Chalk Forination. 60 
prevalent in these strata, proving satisfactorily that it was external 
in its origin. 
No internal organization of structure is discernible in these 
bodies. They are intensely hard, and the most difficult of all the 
fossils to reduce to a fine powder. 
Another abundant supply of phosphate of lime is derived from 
lumps of various sizes, utterly shapeless. These are always of a 
light reddish-brown colour : when first dug they are very soft, and 
never attain a greater hardness than that of soft white chalk. 
Their specific gravity is small compared with the former nodules. 
In a few instances, specimens have been found which unite the 
characteristics of both classes ; the external portion consisting of 
the latter. These lumps are invariably rich, as the subjoined 
analysis indicates : the specimen is from the Dippen Hall pits : — 
Insoluble silicious matter, with a little clay . . 7 "18 
Soluble silica 3-28 
Organic matter . . . . . . . 2*49 
Phosphoric acid (equal to 55 '96 of bone-earth 
phosphate) 27-13 
Carbonic acid . . . • . . . 8 77 
Lime 39-8.5 
Magnesia ........ "96 
Oxide of iron and alumina . . . . .10*60 
Traces of fluorine — 
100-26 
But there is another description of organic remains which is 
found in still greater profusion than any of the preceding. They 
consist of very dark brown lumps of every form and size ; some 
are microscopically small, others attain the weight of 3 and 4 lbs. 
each: they are both heavy and hard. It appears that these sub- 
stances at one period must have existed in a soft plastic state, 
since many of them are agglutinized to the surfaces of the 
syphoniae, corals, shells, teeth, and wood. Some very perfect 
pectens are covered up, both internally and externally, with these 
amorphous bodies, which cannot be detached without breaking 
the shell. 
This substance seems to be identical with that which has been desig- 
nated by Dr. Mantell, in his ' Medals of Creation,' p. 431, as ' Mollus- 
kite, or the Carbonized Remains of the soft parts of Mollusca.' In 
introducing this subject he says, — 
" I will offer a few remarks on a carbonaceous substance resulting 
from the gelatinous matter of which the soft bodies of these animals are 
composed, and for which I propose the name of Molluskite, to indicate 
its nature and origin. 
" This substance is of a dark-brown or black colour, and occurs either 
in shapeless masse?, which are irregularly distributed among the shells 
