1869. ]. TATE AND HOLDEN—IRON-ORES WITH BASALTS. 161 
thickness in the same direction. Wherever a fine sediment occurs, 
even though in the conglomerate, plant-remains are present. 
The plant-layer, which is mined and used as a flux, is of low 
specific gravity, and is not sufficiently rich in iron to be valuable for 
smelting. The following analysis of this rock is communicated by 
Dr. J. Apjohn. 
Water ......... eRe te renee tane seen neue ana shee eves tat eee 25°78 
Silica with a little alumina .....................scceeeceecenescteceeeens 36°40 
(Reroxid ero belrora mean sss se ceierene coalseanees soe salcind sedaue celeSinalaten 9-12 
Alumina and other oxides (by difference) ...............2eseseeeee 28°70 
100-00 
Percentage of metallic iron.................0ecececeretecteneeeeeneeeeeees 6°36 
In a neighbouring pit on the N.E. side of the line of railway there 
is exhibited a similar section. The conglomerate-bed presents a 
maximum thickness of 10 feet, thinning away to the N.E., and with 
the underlying shales dipping in the contrary direction. The shales 
are about 6 feet thick and are underlain by lignite, which surmounts 
an amygdaloidal basalt. 
2. Relation of the Strata to the Basalts.—The railway-cutting 
about a quarter of a mile to the N.E. of the ochre-pits presents a 
section (fig. 4), which enabled us to place the fore-mentioned sedi- 
mentary ores, shales, and lignite in juxtaposition with a subsequent 
basaltic flow (1). 
Fig. 4.—Section in Ballypalidy Railway-cutting, north side. 
pr 
| 
| 
A thin band of impure lignite (3), with or without a clay band 
below containing plant-remains, and always accompanied by an over- 
lying stratum of clay (2),is seen in one place following the undulating 
line of the upper surface of a concretionary basalt (4), which latter 
is superimposed upon a ferruginous series of iron-ore and the under- 
lying bole (5) and lithomarge (6), Elsewhere the basalt above the 
pisolitic iron has been eroded, and the lignite series rests upon the 
pisolitic iron-ore or inferior basalt. 
The continuity of the lignite-band of these sections with that of 
the underlying plant-beds and conglomerates in the pits some little 
distance to the west, is not traceable step by step; but there is little 
doubt that the several portions visible are parts of one stratum. 
