On the riiosphoric Straia of the Chalk Formation. 71 
be dismissed without recommending that it sliould be turned to pro- 
fitable use by an exaniinatjon into the composition of the fossihterous 
portion of tlie Kentish ragstone whicli is here described. 
Tiie fossils discovered by Professor Henslow, noticed above, and the 
nodules examined nearly 30 years ago by M. Berthier, appear to have 
been princii)ally composed of this moUuskite. 
M. Berthier's analyses of them, takm from a rock of the green-sand at 
Havre, through which they were disseminated, gave — 
Phosphate of lime . . . .57 
Carbonate of lime .... 7 
Carbonate of magnesia ... 2 
Silicate of iron and alumina . . 25 
Water and bituminous matter . 7 
98 
Having thus recorded the results of examinations made upon 
the characteristic tjpes of the fossils of the upper green sand 
phosphoric beds, it is necessary to proceed to the investigation of 
the component parts of the aggregate masses and of the soil which 
envelops them ; and also to describe the method which has been 
adopted in digging and preparing them for use. This portion of 
the inquiry is in fact the most important in its agricultural 
bearings. 
From one of the pits on Dippen Hall farm, a mass weighing 
30 lbs. was indiscriminately taken out of a rich fossiliferous vein. 
This mass was thoroughly washed, and the fossils carefully sepa- 
rated ; these were of all sorts and sizes, amounting to 61 per cent, 
of the whole: 10,000 grs. weight of them were broken, and they 
gave an average composition of — 
Insoluble silicious matter . . . 9 "84 
Soluble silica . . . . . . 2*36 
Organic matter . . . . . 3'26 
Phosphoric acid (equal to 59 "60 of bone- 
earth phosphate) 27-60 
Carbonic acid , . . . . 6'96 
Lime ....... 44*56 
Magnesia and loss . . • . . '81 
Oxide of iron and alumina . . . 4 '61 
100-00 
The residuum of marl washed oft' from the fossils, when dried, 
gave — 
In coarse lu fine 
particles. mud. 
Insoluble silicious matter . . . 21*85 26*25 
Soluble silica 20-18 18*11 
Organic matter . . . . .6*25 5*95 
Carried forward 
48*28 
50-31 
