MINTARO GOLDFIELDS.
The Government Geologist, on Wednesday, forwarded to the Commissioner of Crown Lands a report regarding the gold-diggings in the Hundred of Stanley, near Mintaro. Mr. Brown says: —
“The bed rocks consist of sandstone, quartzite, clay, sandy and calcareous slates, kaolinized slates, and sandstones, blue crystalline, and yellow limestone, striking north and north-north-east, and dipping invariably to the westward at various angles from 30° to nearly vertical. The sandstone and quartzite beds occupy the highest portions of the hills and ridges, the slates and soft slaty rocks the valleys, the same beds apparently recurring in more or less parallel lines, owing probably to the presence of a series of meridional faults, some of the lands of kaolinized slate or mudstone are dark blue or black in colour owing to their containing a small percentage of carbon. In the adjoining Hundred of Clare, Section 306, a shaft as been sunk through one of these beds under the supposition that a coal seam was likely to be found. There is no probability, however, that such will be found in these rocks. The sandstone and quartzite are penetrated to a small extent by horizontal and inclined quartz veins and veins of brown iron ore mixed with quartz, which probably may be auriferous in some cases. Besides these there are irregular quartz and ferruginous veins traversing the softer slates, which veins may also contain gold. A vein of calcspar and ferrocalcite also occurs in one place.
“Resting on the upturned edges of the bed rocks here and there in outlying cappings are patches of ironstone, ironstone and quartz conglomerate, and quartz pebble drift of tertiary age, similar to the older gold drift of the Barossa and Echunga diggings. On Sections 115 and 116 these cappings are specially noticeable, filling in one place on the latter section a deep ‘gutter’ in the kaolinized slate and sandstone bed rock. They are outlying portions of a wide area of tertiary formation, spreading over the country from Gawler northwards. Geological sections showing it are frequent in the neighbourhood of Hamley Bridge, and between that place and Stockport. It is very probable that these drifts will be found to contain gold, and that some portions will be payably auriferous.
“The alluvial gold diggings are on Section 2153 and a small reserve adjoining it. The workings are in a gully flat on a low rise adjoining the gully and in a creek into which the gully runs. The gold is found on two bottoms, viz.—in the surface loam and gravel, which extends to the depth of from 6 in. to a foot or two and in the red clay and wash beneath which rests on the bedrock. Some of the gold is considerably water worn, some but slightly so and exhibiting traces of the original crystallization. Nuggets of a few ounces have been found. It is of unusually good quality. On Section 2159 a small quantity of gold has been obtained from the first bottom and colours are reported to have been obtained on Sections 124, 116, and others. No large or well defined quartz reefs or igneous dykes are visible on this field, although they may exist and be hidden beneath the deep covering of soil and alluvium which prevails here. It is possible that the gold found has been derived from small kaolin and ironstone veins similar to those in which it has been found to occur at Echunga. The rock formations of the district generally are favourable to the occurrence of gold. Places where there are cappings of tertiary gravel and conglomerate, as well as the gullies and creeks, where favourable conditions for prospecting exist, may be tested all over the district with a reasonable hope of finding other auriferous areas.”
