THE CRANBOURNE METEORITES 
29 
the iron there has been little or no selective leaching or migration 
of the nickel relative to the iron, since the ratio of Fe/Ni is 
practically the same as that of the fresh iron. Presumably, 
therefore, the nickel has entered the composition of the limonite 
forming the scale. 
Nodules 
All the Cranbourne irons are characterized by the presence in 
them of numerous nodules. These have been found both in the 
iron (Plate IV, Fig. 2) and in the limonitie scale or crust. In 
the Cranbourne No. 2 mass, five nodules can be observed in the 
polished face of the iron, which has an area of 120 x 90 nun.; 
the largest of these nodules measures 30 x 20 mm. One in the 
Langwarrin iron measures 45 x 15 mm. Those found in the 
Cranbourne No. 8 vary from 12 5 x 12 5 mm. to 25 5 x 19 mm. 
The smallest nodule found was in the Cranbourne No. 7 ; it 
measures only 1 mm. across, and consists of graphite. Another 
graphite nodule from the same iron measures 14 x 15 mm. ; the 
largest nodule, a composite one, measures 25 x 15 mm. The 
largest nodule from the Pakenham iron (Cranbourne No. 6) 
measures 40 x 30 x 21 nun., and weighs 45 grams. The largest 
recorded occurred in the Cranbourne No. 1 iron, and is 50 mm. 
across. 
A few of the nodules have a sub-spherical shape, and a few are 
ellipsoidal, irregular, or bean-shaped, but the majority approxi- 
mate to a triaxial ellipsoidal shape, with average dimensions 
about 14 x 9 x 6 mm . 
The composition of the nodules varies somewhat. A few consist 
solely of graphite, or troilite, or of pyrrhotite, but the majority 
are mixtures of graphite and pyrrhotite. A few consist of 
mixtures of graphite and troilite. The majority have a rim of 
schreibersite (Plate IV, Fig. 4), and veinlets of limonite traverse 
cracks in the sulphides and sometimes intervene between the 
sulphide-graphite cores and the phosphide rims. 
According to Flight (1882), the nodules in the Cranbourne No. 
1 iron consisted of troilite surrounded by thin layers of graphite 
and daubreelite. The nodules in the Beaconsfield and Cranbourne 
No. 2 irons are also reported to consist of troilite and are said 
to decompose to stilpnosiderite (Walcott, 1915, p. 31). It is 
doubtful, however, that the sulphides in these nodules were tested 
by etching, and in view of the preponderance of pyrrhotite over 
troilite in the nodules so tested from the Pakenham and the four 
Cranbourne irons under discussion, it seems likely that some of 
the substance recorded as troilite may have been pyrrhotite. 
