ural purposes remunerative.

The term coprolites has been made to include all kinds of phosphatic
nodules employed as manures, such, for example, as those obtained from
the Coralline and the Red Crag of Suffolk. At the base of the Red Crag
in that county is a bed, 3 to 18 in. thick, containing rolled fossil
bones, cetacean and fish teeth, and shells of the Crag period, with
nodules or pebbles of phosphatic matter derived from the London Clay,
and often investing fossils from that formation. These are
distinguishable from the grey Chalk coprolites by their brownish
ferruginous colour and smooth appearance. When ground they give a
yellowish-red powder. These nodules were at first taken by Professor J.
S. Henslow for coprolites; they were afterwards termed by Buckland
"pseudo-coprolites." "The nodules, having been imbued with phosphatic
matter from their matrix in the London Clay, were dislodged," says
Buckland, "by the waters of the seas of the first period, and
accumulated by myriads at the bottom of those shallow seas where is now
the coast of Suffolk. Here they were long rolled together with the bones
of large mammalia, fishes, and with the shells of molluscous creatures
that lived in shells. From the bottom of this sea they have been raised
to form the dry lands along the shores of Suffolk, whence they are now
extracted as articles of commercial value, being ground to powder in the
mills of Mr [afterwards Sir John] Lawes, at Deptford, to supply our
farms with a valuable substitute for guano, under the accepted name of
coprolite manure." The phosphatic nodules occurring throughout the Red
Crag of Suffolk are regarded as derived from the Coralline Crag. The
Suffolk beds have been worked since 1846; and immense quantities of
coprolite have also been obtained from Essex, Norfolk and
Cambridgeshire. The Cambridgeshire coprolites are believed to be derived
from deposits of Gault age; they are obtained by washing from a stratum
about a foot thick, resting on the Gault, at the base of the Chalk Marl,
and probably homotaxeous with the Chloritic Marl. An acre used to yield
on an average 300 tons of phosphatic nodules, value L750. About L140 per
acre was paid for the lease of the land, which after two years was
restored to its owners re-soiled and levelled. Plicatulae have been
found attached to these coprolites, showing that they were already hard
bodies when lying at the bottom of the Chalk ocean. The Cambridgeshire
coprolites