05 
The Green Sand here consists of fine marl, highly charged 
with green chloritic grains, angular boulders, and hard, 
dark-coloured nodules of phosphatic matter, often covered 
with Plicatulee, Serpule, &c. The fossils are true upper 
Green Sand species, and appear for the most part to have 
lived and died on the spot ; all the shells are filled with the 
game substance as the nodules, which are often of a black 
colour, but sometimes brown, and contain shells and fish 
remains. 
At Potton and Sandy, in Bedfordshire, in an earlier 
formation, (the lower Green Sand) there is a curious con- 
glomerate, about a foot thick, overlaid and underlaid by 
variously coloured sands, the lower portion of which con- 
tains layers of oxide of iron, twelve feet thick. In this 
conglomerate the nodules of Phosphatic matter occur. This 
conglomerate consists of a ferruginous sand, more or less 
indurated, rolled pebbles, hardened clay, and light-brown 
phosphatic nodules, which often contain fragments of shells. 
At Sandy this iron-sand forms a hard stone, mainly com- 
posed of small pebbles of quartz, sandstone, and mica, with 
numerous phosphatic concretions, which are here very 
irregularly distributed, and are occasionally altogether 
absent. Most of the fossils associated with them are 
derivative, and very much water-worn and eroded. The 
shells were probably washed out of the Kimmeridge 
and Oxford clays, the fish remains, teeth, and ichthyodoru- 
lites, from the upper and middle Oolites. A few shells which 
are not rolled belong to the lower Green Sand, and lived and 
died where they are found. 
In the neighbourhood of Ely, pits have been opened, one 
to the depth of nearly six feet, and another from eight to 
nine feet; the former contains three layers of phosphatic 
