Page:Transactions NZ Institute Volume 15.djvu/479

“This mineral was first discovered by Mr. Traill, occurring in detached masses of irregular form and considerable size in the superficial gravels and peat deposits at most points along the low eastern shore of the Chatham Islands. It appears to have no connection with the brown coal and lignite deposits which occur in the same island; nor could Mr. Traill discover any distinct bed or seam of this mineral. It is very interesting on account of its highly bituminous character, resembling that of the oil-shale found at Mongonui, Auckland.”

A similar mineral is found on the Auckland Islands, and is mentioned by Dr. Hector (Trans. N.Z. Inst., vol. ii., p. 183).

Bituminous Shale.—A mineral closely approximating to Torbanite is mentioned by Dr. Hector (First Coal Report, 1866, p. 44) as coming from Awatere, near Mongonui, Auckland. It is very coherent, close-grained, hard and tough, almost elastic, does not show the slightest indications of lamina or cleavage planes, having a smooth semi-conchoidal fracture in every direction. Colour, dull black; perfectly homogeneous; powder, brown or chocolate colour; sp. gr. 1.112; ignites with ease and bursts into flame, which is sustained for a long time and with great vigour. Flame at first luminous and bright, but soon becomes long and smoky. During combustion small oil-bubbles are seen escaping. Heated to dull red heat in closed crucible, 23 per cent. of light, non-coherent, cellular and slightly lustrous coke remains, which burns readily in free access of air to a white ash.

Carbonaceous Shale.—A mineral having the composition of—

occurs at Orepuki, Southland, and is reported on (Col. Mus. and Lab. Reports, xi., p. 11), and another from Blueskin Bay, Otago, is also mentioned (Col. Mus. and Lab. Beports, xiii., p. 21), which is composed of—