366 Proceedings of the Royal Society of Edinburgh. [Sess. 
by s.s. Pieter Faure (1898). The deposit contains 33 per cent, of calcium 
carbonate in the shape of foraminifera shells, many of which have a greenish- 
grey coating, possibly glauconitic ; it also contains finely-divided dirt 
(largely organic), worm-tubes, chitinous fragments, etc. After the removal 
of calcareous and fine matter, the granular residue was divided into two 
portions by simple elutriation, viz. : — 
a. (4 per cent, of deposit), dark greenish-grey, mainly glauconitic. The 
glauconite particles vary widely in size, from the smallest possible up to 
0*3 mm. in mean diameter ; they are mostly not rounded but very ragged 
in outline (suggesting exposure to wave or tidal action); there are a few 
well-defined casts. Residue after separation of glauconite = 12 per cent., 
quartz sand, sponge spicules, and brown organic matter. 
b. (53 per cent, of deposit), white sand with an admixture of full-sized 
dark-green glauconite grains, well rounded. Mineral residue 88 per cent., 
almost pure quartz sand. 
The dried greensand as a whole is composed, in round numbers, of 
Calcium carbonate 
. 33 per cent. 
Glauconite grains 
. 10 „ 
Minerals .... 
. 47 „ 
Fine and miscellaneous 
• 10 
100 
There is no appearance of incipient decomposition on the grains of 
fraction a ; some of those of fraction b, however, have much the same 
superficial incrustation as Albatross grains. 
The flocculent glauconite prepared from Agulhas Bank greensand is 
darker and more glaucous than that from the Albatross material, which is 
bright chrome-green in colour. Tuscarora glauconite is darker than the 
latter and more brilliant than the former. Chemical analysis of the 
purified glauconites gave the results stated below ; Collet and Lee’s analysis 
of Tuscarora glauconite is quoted in the third column : — 
Albatross. 
Agulhas 
Bank. 
Tuscarora. 
Ignition loss .... 
7-12 
7-56 
7-00 
Si0 2 
49 12 
51-15 
47-46 
A1 2 0 3 
7-09 
7 61 
1-53 
Fe 2 0 3 
25-95 
18-83 
30-83 
FeO 
0-89 
2-78 
3-10 
MgO 
3-10 
4-54 
2-41 
k 2 o 
7-02 
7-80 
7*76 
100-29 
100-27 
100-09 
