1869. ] TATE AND HOLDEN—IRON-ORES WITH BASALTS. 153 
iron band is seen gently undulating, and is traceable for a further 
distance of a mile in both an easterly and westerly direction. The 
«‘ mineral” is mined by approximately level drifts, running N. 40° E. 
and at right angles to the face of the workings; many of the levels 
have reached to a distance of two hundred yards. 
The following section is in descending order, numbered from 
above :— 
1. Hard, compact, columnar basalt. Where exposed to weather- 
ing influences, it is decomposed at the lower surface for 
afoot or so, within which there isan argillaceous mineral, 
probably a magnesian clay, termed by the miners “ rock- 
grease.” 
2. Pisolitic iron-ore. This band consists of a dense red ochre- 
ous paste, with included spheroids, composed chiefly of 
a mixture of magnetite and red hematite. In the upper 
part of the band the spheroids are occasionally as large 
as hazel nuts, but more frequently of the size of peas, and 
densely crowded. The size and frequency of the nodules 
Giminish downwards ; .sc.cs....ssceseccceeeseees Thickness 2 ft.-2 ft.6 in. 
and the ore passes into 
. Indurated ferruginous ochre, of a reddish-yellow colour, 
breaking up into irregular lumps. ............ Thickness 4 ft. 
It merges insensibly into the underlying band of 
. Lithomarge. A variegated rock, with a predominating blue 
colour and greasy feel, breaking up into small sub- 
spheroidal blocks. The whole mass might readily be 
mistaken from a distance for some of the variegated marls 
of the Keuper series .........ce0........-.-.00-.... Thickness 25 ft. 
The lithomarge graduates downwards into a basalt exhibit- 
ing a concretionary structure, the outer coats not distin- 
guishable from the lithomarge, while the kernel is a com- 
pact basalt. 
ioe} 
ib 
oi 
Fig. 1.—Section at Belumford. 
or 
. 9% 
ae 
7S 
SSS 
2. Section at Belumford, north-west extremity of Island Magee :— 
1. Columnar basalt, with two or three inches of decomposed 
rock below. 
2. Pisolitic Iron-ore. The upper two inches with little or no 
ochreous matrix: the spheroids large, and now and then 
a thin lamina of the ore. The ochre increases in quantity 
with the increase of depth, and the iron-ore merges into 
BUOLG nates stbascveressesnass scusluctyvavesetctte Thickness 2 ft. 6 in. 
mM 2 
