The Pamphlet Collection of Sir Robert Stout: Volume 64
It was shown in a former paper that limestone as a geological formation occupies an immense area of Otago, but it does not follow that the supply of lime for industrial purposes is equally extensive, many of the calcareous rocks being incapable of producing lime of good quality. There is, however, no scarcity of lime suitable for building and agricultural purposes throughout the province. It is known to exist in considerable quantities in the following districts:—Oamaru, Otepopo, Waihemo, Maniototo Plains, Waikouaiti, Lower Harbour, Peninsula, Waihola, Waimea, Winton, Aparima, Waiau, and Wakatipu. These localities are so widely dispersed that we may safely calculate on a supply being available for any demand that can arise.
The only natural cement hitherto discovered in Otago is the well-known Septaria or cement boulders of the Moeraki district, which resemble in every respect the English stones from which Roman cement was originally manufactured. According to Dr. Haast, the boulders follow the coast from Shag Point to the Terapupu Creek, then run in a straight line to the Little Kiwi Creek, which is struck at a point about half a mile from the sea. In the first four miles the deposit is a mere line of boulders lying on the beach or imbedded in the cliffs, but on leaving the coast it expands into a belt I from 20 to 80 chains wide and 5½ miles long.
Many of the volcanic clays that exist in such profusion along the sea board from Saddle Hill to Oamaru possess cementitious properties similar page 114 to the Pozzuolanas of Italy and the Tyrass of the Rhine, but as they are only used in combination with lime, they will be considered along with the other aggregates, or as a component part of artificial cements.
The aggregates proper consist of shingle, gravel, and sand, which have an almost universal distribution throughout the province.