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 Suffolk beds have been worked since 1846; and immense quantities of coprolite have also been obtained from Essex, Norfolk and Cambridgeshire.
Samples of Cambridgeshire and Suffolk coprolite have been found by A.
91): - 98'734 An ichthyo-coprolite from Tenby was found to contain 15.4% of phosphoric anhydride.
Coprolite is reduced to powder by powerful mills of peculiar construction, furnished with granite and buhrstones, before being treated with concentrated sulphuric acid.