59 
The analyses show one fact of great economic value, namely, that the 
nodules are concentrates 1 , a characteristic in common with those in similar 
beds in other parts of the world, which give a much higher percentage of 
phosphoric acid. 
Penrose 2 has described eleven varieties of nodules of variable phosphoric 
acid content, all of which are usually found in association. Probably the 
whole eleven could be found at Mornington with diligent search. 
The percentages of nodule in the talus on the shore varies from 5 to 20 per 
cent. There is little doubt that, if a layer giving a good percentage of phos¬ 
phoric acid were discovered, there would be no lack of nodules. The size 
varies from the size of a pea to 4 feet in greatest diameter. The presence of 
as much as 2 J per cent, of phosphoric acid in the marl appears to indicate that 
nodules giving as much as 5 per cent., or even more, are present, since it is 
to the nodules that the marls owe most of their phosphoric acid. 
The nodules were used in the early days of the State for the manufacture 
of hydraulic cement. This cement is spoken of by old residents of Morn¬ 
ington as being of excellent quality. 
[29.10.12.] 
NOTES ON FRENCH ISLAND. 
Bij E. J. Dunn , F.G.S., late Director, Geological Survey. 
Coal, Iron Ore, and Clay. 
On the south-west corner of French Island, at the head of Westernport 
Bay, is the township of Tankerton, where some basalt belonging to the Older 
Basalt series is exposed, and forms a very prominent point. Northward 
from Tankerton the west coast is sandy, no rocks outcrop, and the sandy soil 
continues inland as far as Mount Wellington from the northern coast. Mount 
Wellington is the highest point in the island though it rises only about 275 feet 
above sea-level. k 
Various materials from this locality have been assayed or tested at the 
Geological Survey Laboratory with the following results :— 
Assays. 
— 
— 
Gold. 
Silver. 
Iron. 
Insoluble. 
Phospho¬ 
rus. 
Sulphur. 
599 
Ironstone siliceous 
Trace 
Trace 
34-16 
33-98 
0-113 
0-095 
600 
,, limonite 
9 9 
9 9 
49 64 
8-93 
0-220 
0-103 
601 
,, siliceous 
9 9 
9 9 
29 86 
4301 
0-350 
0-051 
602 
,, limonite and 
9 9 
9 9 
41 73 
8 '18 
0143 
0-036 
carbonate of 
iron 
603 
,, limonite im- 
99 
99 
36-52 
30-31 
0-234 
0-016 
604 
pure 
,, limonite very 
9 9 
9 9 
27*45 
47 67 
0*053 
0.112 
605 
impure 
Ferruginous grit 
9 9 
9 9 
26-03 
49*27 
0-230 
0-058 
No. 602 was smelted and a small ingot of iron obtained. 
1 Cf. analyses of matrix containing nodules, Table II. 
2 R. A. F. Penrose. Deposits of Phosphates of Lime, Geo. Surv., Bull., U.S.A., vol. vii. 
