On the Pliosphoric Strata of the Chalk Formation. 77 
saije of water, that drainage is rendered indispensable whenever 
they happen to occur near the surface in cultivated grounds ; and 
the springino; out of water on the side of a hill has frequently 
indicated the presence of the bed, when it had been superficially 
covered up by drift. 
Dr. Fitton again specifically mentions the occurrence of this bed in 
his memoir at i)ages 111, 116, 117, 145, 157, 181, and 209. He de- 
scribes these fossils as nodules and irregular masses which resemble 
coprolite in their chemical composition, though no traces of animal 
structure are apparent in them. Others are of irregular figure, sur- 
rounding or incorporated with fossil remains, especially of ammonites, 
the interior of which is filled with matter of the same kind — all contain- 
ing phosphate of lime. 
Dr. Mantell also, in his 'Geology of the S.E. of England,' says, at 
page 172 — "At about three miles N.W. of East Bourne the green 
(lower) sand is covered with a thin layer of gault, which occurs imme- 
diately beneath the surface ; the sand abounds with rounded fragments 
of cornferous wood that occur on the road side, near the Folkingtou road. 
'I he specimens are incrusted with a covering of grey sand containing 
small pebbles of quartz, and internally are of a reddish-brown colour. 
Tlie wood is calcareous, and bears a good polish, the transverse sections 
displaying, in a distinct and beautiful manner, the radial insertions and 
annular markings which denote the annual growth of the tree," &c. &c. 
Tliis description so minutely agrees with the appearance of the phos- 
phoric bed as found elsewhere, that there is scarcely a doubt of its 
identity. It is highly probable, too, that the fossil wood, if analysed, 
would be found richly phosphoric, not carbonic. 
Again, taking the Farnham beds as a type and illustration of 
the entire range, the particulars there noticed are recorded below, 
'i'he general mass of soil in which the fossils are imbedded in this 
stratum differs essentially from the phosphoric marl of the upper 
green-sand, inasmuch as the enveloping marl of the latter largely 
partakes of the phosphoric nature of the fossils, whUst the former 
seems to be destitute of it, excepting that which is derived from 
the decomposition of the fossils. The following is an analysis of a 
mass, from which the principal fossils had been jiicked out : — 
Insoluble silicious matter 
. 75-46 
Soluble silica 
. 8- 12 
Organic matter 
2-30 
Phosphoric acid 
. 0-64 
Carbonic acid 
5-64 
Lime . . . . . 
2-01 
Magnesia . . . . 
0-18 
Oxide of iron and alumina 
. 5-59 
99-94 
On the east of the town of Farnham, near Bourne Mill (this 
