NODULE BEDS. 
9 
have received some 50 per cent, of phosphate of lime from the 
quantities of bones 'with which they were associated on the 
sea-shore He explained the rarity of bones of terrestrial 
Mammals, as compared with those of Cetaceans, from the fact 
that the former came on to the beach in a different state of pre¬ 
servation to the latter, which were derived from Diestian beds. 
The fresher bones would be more easily acted on by the sea than 
those already mineralised. 
Mr. E. Charlesworth,* later in the snme year, noticed that the 
phosphatic matter often encloses the fangs of the sharks’ teeth, the 
tooth proper being left free, and that it is only such teeth as have 
been derived from the London Olay that are thus included in 
phosphate, whence he concluded that all the phosphatic stone (as 
distinguished from bones) in the Crag had been derived from the 
London Clay. 
In 1870 Prof Lankesterf treated of the composition of the 
Nodule Bed at length, and described and figured some of its 
more remarkable fossils. He also pointed out that the Nodule 
Bed occurs beneath the Coralline Crag as well as beneath the 
Red Crag. He gave a detailed account of the sandstone nodules 
that occur in the bone-bed, which he calls box-stones, though 
the majority contain no fossils; the name boxes has been given 
by the phosphate-diggers to those that show hollow moulds of 
shells on being broken. After examining a large number he 
concluded that all have been derived from one deposit, of Diestian 
age; and that they are probably coeval with the Lenham sand¬ 
stone of Kent. They represent a period separated by a wide gap 
from the Red and Coralline Crags, Lists of the fossils found in 
these stones, and of the Mammalia from the bone-bed are given. 
In 1871 Prof. PrestwichJ gave further particulars of the 
Nodule Bed, and described the section at Sutton, where the 
phosphatic nodules are found beneath the Coralline Crag, 
Subsequently Messrs. Whitaker and Dalton gave details of all 
the sections in the Memoirs of the Geological Survey relating to 
the Red Crag district. Those referring to the Nodule Bed are 
the ones on the Eastern end of Essex (Walton Naze and 
Harwich)” 1877, on “Ipswich, Hadleigh, and Felixstow ” 1885, 
and on Aldborough, Framlingham, Orford, and Woodbridge ” 
188fi. 
But for the economic value of the Nodule Bed, and the exten¬ 
sive scale on which it has been worked, we should know little 
about the interesting derivative fauna contained in it. This 
bed is one of the same kind as those at the base of the Chalk, and 
in the Lower Greensand, in Cambridgeshire, Bedfordshire, etc., 
all of them being of a conglomeratic or gravelly character, and 
containing so-called “ coprolites,” or fossils and nodules composed 
chiefly of phosphate of lime. 
* Geol. Mag.,, vol. v. pp. 577-580. 
f Quart. Journ. Geol. ISoc., vol. xxvi. pp. 493-514. 
X Ihid., vol. xxvii. pp. 116-118, 326, 327, 341, 347-349. 
