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proved the ore body to be irregular in thickness, varying from 2 to 30 ft.

There are many other promising copper lodes in the West Pilbara field which cannot be worked owing to the fact that at the present ruling price of copper only ores of a value between 20 and 30 per cent. will pay to work on a small scale.

Copper deposits other than those mentioned cover a wide extent of country, and under more favourable mining conditions seem to be capable of yielding in the future a considerable quantity of copper ore.

Lead.—The production of lead in Western Australia, though at one time giving indication of rising to the dignity of an important industry, has not come up to the highest expectations owing to much of the ore not containing sufficient silver to pay for extraction. The year 1848 saw the first discovery of lead ore on the Murchison River, at what is now known as the Geraldine River. The chief sources of supply have been from the mines in the Northampton district, which produced practically the whole of the lead ore in the State. Up to the close of 1910 33,644 tons of lead ore valued at £364,756 have been exported from that district, while up to the same date 602.85 tons of lead ore, containing 290 tuns of metallic lead valued at £3,811, have been reported to the Mines Department.

The lead ores of the Northampton district are found in the ancient crystalline rocks which make up the fundamental complex. These are traversed by a series of basic dykes, which bear an intimate relation to the lead lodes.

Lead ores also occur in the Ashburton district, and a deposit of some promise has been more or less perfunctorily worked at Uaroo. The ore deposit of Uaroo lies just to the west of the junction of a large area of granite, which occupies an extensive tract of country in this portion of the State. The ore-bearing area of Uaroo is occupied by one geological formation, which consists of a continuous series of sedimentary rocks, some bands in which have undergone more or less mechanical deformation. The beds consist of quartzite and phyllite, which have a steep dip to the north-east. The lead lode is a quartz reef of very variable dimensions which runs generally north and south. The deposit has yielded up to the close of 1910 1,224 tons of lead ore (chiefly galena), which has been valued at £10,863.

It is more than probable that other lead lodes will be actively exploited when transport and other expenses have been materially reduced.

Tin.—The development of the tin deposits of the State has been considerably retarded by conditions tending against operations on a large scale. Such disadvantages, however, are in some localities being gradually overcome.

The total quantity of tin ore raised in Western Australia up to the close of 1910 amounts to 12,252 tons valued at £920,011. Tin appears to have first been discovered in Western Australia toward the end of 1888, and has since been found to occur in several widely-separated localities in the Kimberley district, the Pilbara goldfield, the Thomas River in the Gascoyne Valley, the Murchison, Coolgardie, and Greenbushes.

There are, however, only two districts in the State from, which any considerable output of tin has been reported—Greenbushes and the Pilbara goldfield. From the former locality 7,635.99 tons of tin ore have been raised, of which 7,486.05 tons represent the yield of stream tin and 149.94 tons of lode tin. Pilbara has produced 4,614.69 tons of tin, of which amount 4,327.47 tons represent the output of stream tin and 287.22 tons of lode tin.

Wherever the tin deposits of Western Australia have been examined they are invariably found to fall naturally into two distinct geological categories:—(1) Superficial deposits, which include (a) the alluvial deposits and (b) the residual sands, gravels, etc.; and (2) deposits in country rock, which embrace (c) tin-bearing granite and allied rocks and (d) tin-bearing dykes.