7'2 On the Fko^sphoric Strata of the Chalk Formation. 
In coiirsc 
particles. 
mud. 
Brought forward 
. 48-28 
50-31 
Phosphoric acid .... 
. 7-80 
10-38 
Carbonic acid .... 
. 10-91 
10-34 
Tjime ...... 
. 20 - 58 
19-87 
Magnesia ..... 
. 1-59 
•87 
Oxide of iron and alumina 
. 8-18 
6-18 
Potash and soda not estimated. 
97-34 
97-95 
About 30 or 40 tons of this phosphoric marl have been dug 
upon Dippen Hall this spring for the purpose of agricultural 
experiments. The plan adopted in digging was to fill the richest 
portions of the marl into bags (the very large fossils being picked 
out) ; it was then carted to the farm and placed under cover: it 
has since been sifted, after it became dry enough for that purpose. 
The portion of the marl which passed through the sieve (all the 
fossils having been first separated from it) gives on analysis — 
Insoluble silicious matter . . . . .32-81 
Soluble silica 29-14 
Organic matter . . . . . . .3-02 
Phosphoric acid (equal to 13-63 bone-earth phos- 
phate) . . . . . . . .6-61 
Carbonic acid . . . . . . .2-30 
Lime . . . . . . . . . 9'53 
Magnesia 1*97 
Oxide of iron and alumina . . . . . ll"46 
Potash 3-10 
Soda (none). — 
99-94 
The part retained upon the sieve, being about two- thirds of the 
whole quantity, consisted of indurated pieces of marl and small 
fossils imbedded in it. This, when suflficienlly dried, was ground 
up in a mill erected for the purpose. The average of this mass 
contains — 
Insoluble silicious matter ..... 26*83 
Soluble silica •26-30 
Organic matter . . . . . . . 2-64 
Carbonic acid . . . . . . . 2-35 
Phosphoric acid (equal to 19' 22 of bone-earth phos- 
phate) 9-31 
Lime . 15 24 
Magnesia . . . . . . . . 1 • 43 
Oxide of iron and alumina ..... 13^11 
Potash and soda not estimated. — 
97-21 
