MiNBOBK.] PHOSPHATES OF ENGLAND. 91 
sixteenth to an inch in diameter and are embedded in a sandy matrix. 
Very often the mass has been cemented together by calcareous mat- 
ter, forming irregular patches of conglomerate. There also occur in 
this bed many delicate and beautiful shells of mollusca, which are not 
at all worn, but preserve their most delicate parts intact. Lamelli- 
branchs and gasteropods are numerous. 
Above this bed comes a bed of sand composed largely of grains of 
ironstone, quartz, chert, and Lydian stone. Near the overlying and 
underlying beds there are irregular masses of slightly phosphatic sand- 
stone. 
Next above this sand bed comes the u upper i>hosphate bed." It 
resembles the "lower phosphate bed" in most respects, except that its 
nodules are of a lighter color, and the bed is not cemented by carbon- 
ate of lime, so that it has nowhere been indurated into a conglomerate. 
The siliceous pebbles are the same. 
Overlying this is another bed of sand very similar to the lower 
sand bed. 
Above this comes a clay bed. It has been referred to the Gault, but 
Messrs. Keeping and Bonney think that it is probably the represent- 
ative of a bed of sandy clay belonging to the Lower Greensand. This 
is thought more likely, because phosphatic nodule beds, especially in the 
Cretaceous formation, usually occupy the lines of chronological breaks. 
The overlying bed is another bed of phosphatic nodules. It con- 
tains many fossils and is very similar to the two nodule beds already 
described. This bed is overlaid by the Gault formation. 
Fig. 36. Section at Sandy, Bedfordshire, England, after J. F. Walker. A, sand ; B, oxide of iron 
C, conglomerate; D, sand. 
Sometimes the three phosphate beds mentioned above seem to com- 
bine into one (Fig 36). Sometimes, also, the lower bed is not cemented, 
but is loose and sandy, just like the upper beds. The following sections 
will show the variations in the upper Neocomian deposits : 
Section by W. Keeping and E. B. Tawney, at Spinney Abbey. 
Ft. In. 
f 1. Brown surface earth 1 6 
I 2. Head of blue clay • 9 
A ] 3. Irregular gravelly zone, the pebbles being mostly Hints and coprolites, 
[ about.-.. - ---- ° ^ 
(565) 
