53 
The Rev. P. B. Brodie also read the following Paper 
on Phosphatic and Bone bed deposits in British Strata, 
their economical uses, and fossil contents. 
Within the last thirty or forty years, considerable atten- 
tion has been directed to certain nodular masses, or stony 
concretions found in the Crag, a later Tertiary deposit in 
Norfolk and Suffolk, in the first place, and more recently in 
the Green Sand in Cambridgeshire and Bedfordshire. As 
improvements in Agriculture, and a more scientific knowledge 
of farming have advanced, and the necessity for the use of 
phosphate manures has become more prevalent, the demand 
for this substance has largely increased. 
Many years ago, in 1848, the late eminent Botanist, Pro- 
fessor Henslow, drew public attention to the probable value 
of certain phosphatic nodules abounding in the Crag, in 
Norfolk and Suffolk, and from that time to this they have 
been extensively used for making phosphates, and are largely 
exported to foreign countries. With one exception these 
were all obtained from the Red Crag, which overlies the 
Coralline, or Bryozoan Crag, but Mr. Prestwich mentions 
that exception as an extraordinary and most interesting 
stratum, forming a basement bed, containing some large and 
remarkable derivative boulders, of porphyry and other rocks, 
Oolites and London clay fossils, all more or less rolled, and 
he suggests the drifting of ice as the agent by which some of 
these older rocks were conveyed and deposited in the Crag. 
This basement bed, (about 1} foot thick,) rests immediately 
upon the London clay, and contains the phosphatic nodules 
similar in appearance to those in the Red Crag, with Mam- 
malian and Cetacean remains and foreign boulders. Amongst 
the former are the teeth of Mastodon, Rhinoceros, Deer, and 
Cetaceans; vertebra: and ear bones of a Whale, four skulls of 
