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The Pamphlet Collection of Sir Robert Stout: Volume 66

Varieties

Varieties.

Travertine Limestone is found at Dunstan Gorge, Otago; it makes very white lime. It has the usual porosity of this kind of stone.

Geodic Limestone.—This occurs at Hampden, Otago, and has numerous sparry cavities lined with crystallized calc-spar.

Cellular Limestone occurs at Nelson. This kind has numerous angular cells or holes.

A limestone breccia occurs at Ruataniwha.

Lithographic Limestone.—A lithographic limestone is found at Oamaru; it is a very fine-grained stone, hard and compact; its fracture is conchoidal. It occurs in concretions in the limestone, and not in slabs. The quarry is situated where the Lower Tertiary strata have undergone alterations by the extrusion of submarine igneous rocks, probably during their deposition. An extensive deposit of lithographic limestone also occurs at Abbey Rocks, near Paringa River, Westland, from which locality large slabs could be obtained. Lithographic limestone is also found in the Chatham Islands.

Chalk with black and white flints is found at Kaikoura Peninsula and in the northern part of Canterbury; a very pure bed of this material, which is of value for the manufacture of cement, occurring near Oxford.

Sandstones are very plentiful throughout the Islands, and are very varied in hue. The different kinds may be classed under the following heads :—
a.Siliceous sandstones, in which the cementing paste is a siliceous infiltration.
b.Calcareous sandstone, having carbonate of lime for its cohesive power.
c.Argillaceous sandstones, or claystones, in which clay replaces either of the above substances.page 58
a.The true Siliceous Sandstones are found at the base of the Tertiary and in the Upper Secondary formations, where they are associated with beds of coal.
b.Calcareous Sandstones.—These are confined to the Upper Tertiary rocks, and are variable and concretionary.
c.Argillaceous Sandstones or Mudstones—Claystones.—These, like the last kind, are found only in the Upper Tertiary beds, and are variable.