GEOLOGY AND AI LNERA LS. The mountain and plateau regions consist mainly of Paleozoic rocks, Silurian in the south, Carboniferous in the central portion. and Dovonion in the north, while the northeastern and southeastern coast districts are overlaid with lower Mesozoic strata. There are considerable outcrops of granites and metamorphie rocks in the higher regions. with dikes of volcanic trap, basalt, and greenstone. The great plains are formed by horizontal strata of Cretaceous and Tertiary sandstone, sands, and gravel. Rich and extensive coal beds cover large areas in the State. Gold exists in quartz veins in the Silurian rocks, nail silver, tin, copper, iron. and precious stones are also found.
rivals grazing in importance, and has been gaining, while the latter has de clined. The first Australian gold was mined in New South Wales, and the total value of this product mined to date exceeds that of any other mineral in the State. The an nual output. in recent however, has been exceeded in value by silver and silver lead and by coal, although nearly half the men employed in the mining industry, or 19.350
11899), are engaged in gold-mining. The aver age yield of gold between 1890 and 1900 was twice that of the preceding decade. The output in 1900 was valued at £1,194.521. The production of silver and silver-lead ore was insignificant prior to 1884. when it increased rapidly until 1591. the record for that year not having heen subsequently surpassed. in 1900 the value was £2,004,117. The production of coal in 1900 was valued at f1.068.911. an amount exceeded in only one pre vious year. The decline in copper production from 1590 to 1595 was wholly regained in the latter part of the deeaile, the output in 1900 be ing valued at £425.301. The production of tin in 1900 was valued at £1.12,724—the highest figure attained since 1592. Several kinds of iron ore are mined, and a number of other minerals are obtained in small quantities.