VOLCANIC ROCKS.—CASE IV. 19 
VOLCANIC ROCKS. 
Case IV. 
OLDER VOLCANIC. 
1. BASALT. List No. R 1L 
East of East Creek, Western Port. 
Black, dense and compact: contains 
a few embedded, crystalline grains of 
olivine and of a mineral with a bright 
bronzy lustre on the surface of cleavage. 
2. BASALT. List No. R $. 
West Head, eastside, Western Port. 
_ Greenish-black ; it seems to be an 
intimate mixture of felspar, augite and 
olivine. 
8. BASALT. 
North Melbourne, +sheet 1 N.W. 
Greenish-black, very dense and close- 
grained : contains olivine in crystalline 
grams; suitable for road metal. 
4. Drcomrosrp BASALT. 
Bruthen Creek, Gippsland. 
An earthy mass of mottled appear- 
ance. Surface stained and coated with 
oxide of iron. 
5. NODULE IN BASALT. 
King strect, Melbourne. } sheet 
1s 
BON 
Illustrates the coneretionary form of 
decomposition which takes place in 
basalt and other igneous rocks. 
6. Brown Tron-Ore (Hydrous 
Sesqui-oxide of Iron). 
North Melbourne, 4 sheet 1 N.W. 
Associated with, and doubtless chiefly 
derived from, the iron constituents of 
the older basalt during decomposition. 
7. Brown Iron-One. 
Same locality. 
Very similar to No, 6. 
8. EARTHY HEMATITE. 
Same locality. 
More oxidized than Nos. 6 and 7. 
Portion of a nodule in basalt. 
9. DECOMPOSED BASALT. 
Deep Creek, Hurdy-gurdy. 
Very friable and incoherent; almost 
pisolitic, from the abundance of small 
ironstone nodules. 
10. DecomroseD BASALT. 
Flemington. + sheet 1 N.W. 
Has become a clay, but still exhibits 
the concretionary structure indicative 
of decomposition. 
\ 
11. DECOMPOSED BASALT. 
12. DECOMPOSED BASALT. 
Raleigl’s Punt, Saltwater River. 
4 sheet 1 N.W. 
Has a thick, ferruginous, mammil- 
lated coating. Is rapidly passing into a 
brown, homogeneous clay. 
138. DECOMPOSED BASALT. 
Same locality as last. 
Is also quickly passing into a clay ; 
though not quite so much decomposed 
as No. 12. 
14. DECOMPOSED BASALT. 
Deep Creek, Hurdy-gurdy. 
Of an olive-green color, when freshly 
broken, passing into a homogeneous 
clay. 
15. DECOMPOSED BASALT. 
Forming a red, brown, and white 
mottled clay. 
16. Rep Cray (Earthy). #* 
Map No. R 11. 
Section 7, Bolinda. } sheet 7 N.E. 
Associated with, if not actually re- 
sulting from, the decomposition of 
basalt in situ, and underlying the newer 
basalt. 
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