90 
DEPOSITS OF PHOSPHATE OF LIME. 
fBULL. 46. 
amount varies from 2 to 10 per cent, and is probably due to small 
grains of phosphatic matter iu it. 
Fig. 34. Distorted bed in Cambridgeshire, England; after O. Fislier : Geological Magazine, London > 
1871. A, shelly soil; B, clay or clayey gravel; C, white clay; D, phosphate nodule bed ; E, Gault. 
Phosphatic beds of Cretaceous Lower Greensand. — These beds occur be- 
tween the Coral Rag formation at the base and the Gault on the top> 
Their position with regard to these formations will be best seen in Fig. 
35, section at Upware, Cambridgeshire. 1 The Coral Rag is a coralline 
rock varying much in texture, sometimes loose and porous, and at others 
compact and oolitic or arenaceous. Upon this the Kimmeridge Clays 
rest, probably conformably. 2 But at some places, as at Upware, the 
Kimmeridge Clay has been washed off the Coral Rag, which, in such 
cases, often comes into direct contact with the overlying nodule bed. 
Sometimes, as a result of this destruction, there is a deposit of frag- 
ments of Coral Rag and Kimmeridge Clay immediately overlying the 
Coral Rag formation. 
Fig. 35. Section at Upware, Cambridgeshire ; after W. Keeping. A, Gault and phosphatic nodule 
beds; B, clay, sand, and nodule beds; C, Kimmeridge Clay and Coral Rag; D, junction bed. 
Next in an ascending series comes the "lower phosphate bed.'? 
Mr. Keeping considers this as the first definite bed of the Upware 
Neocomian. It consists of a mass, indiscriminately mixed together, 
of phosphatic nodules and shell casts, fossils, pebbles of quartz, flint, 
Lydian stone, and jasper, besides occasionally a fragment of Coral Rag. 
They are all more or less rounded and worn, though some of them still 
preserve their angular shape. The stones and nodules vary from one- 
^rhe Fossils and Palseontological Affinities of the Neocomian Deposits of Upware 
and Brickhill, by Walter Keeping, p. 4. 
-'Ibid., p. 3. 
(564) 
