(d) Light colored shales; bluish white, olive yellow, gray, etc., 25 feet. This layer, surrounding and joining the mine, is 50 feet thick, and contains many fossils, some of which are shown in the following plates.
(e) Black, or bluish black carboniferous shale, containing four or five “iron bands,” or limonite (marked f), from 1 inch to 1 foot thick. This layer is 225 feet thick, and in addition to many fossils also contains numerous flat-rounded pieces of black shale, of a harder nature than the body of the reef, and generally with a septum dividing the nodules. Water has evidently worn the masses down on each side of this hard division, often giving them the appearance of oyster, mussel and other shells, also of fish and other forms. One such stone amongst many (marked with an arrow) was found just above the hard rock, which here commences.
(g) A trachyitic breccia of specific gravity 2.815. This is of a very tough, horny nature, and of a pale bluish gray color, sprinkled with small particles, both angular and round, of a darker color (3 feet).
(h) Compact augitic, or hornblendic, very tough (8 feet).
(i) Seamy do. do., closely resembling basaltic trap, 4 feet worked, but of unknown depth. The total depth of the working represented in the diagram is 300 feet, and was the deepest working in the Kimberley mine at the time that it was abandoned.[[29]]
Fig. 2. This represents a diagrammatic section of the interior of the Kimberley mine, from the surface to a depth of about 300 feet, and made up as follows:
(a) Grass, etc.
(b) Red sand as in Fig. 1, 6 feet.
(c) Calcareous tufa, 6 feet.
(d) Yellow diamondiferous ground, 25 feet. At the junction of the “yellow” and “blue” the change of color previously alluded to is shown, and also the porous layer with water oozing from it, and trickling down the “face” of the claim.