New South Wales

NEW SOUTH WALES, a state of the Commonwealth of Australia, lying in the south-east, and occupying 309,432 sq.m. or 10.4% of the continent. From the east coast (Point Danger Cape Howe, 700 miles) to the western boundary which runs for 240 miles along longitude 141° E., the average breadth is c. 65o miles. The northern boundary lies along lat. 29° S. and further east, along the Upper Darling (Barwon-Macintyre-Dumaresq) streams and thence along a crooked line of highland divide (Mac pherson Range, etc.) to Point Danger. The southern boundary is formed by the middle and upper Murray to the head of the Indi (Forest Hill), thence in a straight line south-east to Cape Howe.

Physiographically four main divisions may be distinguished, corresponding to fairly well-marked climatic and economic areas.

(i.) Eastern Highlands, the most striking, as also the most decisive, of the relief features, consists of a belt of plateaux extending from the Macpherson Range on the north to the Aus tralian Alps (q.v.) on the south. (See AUSTRALIA : Geomor phology; Queensland.) In the north the New England Plateau (c. zoo miles long, 70-80 miles broad, with c. 9,000 sq. miles lying above 3,00o ft.) rises in its centre to c. 5,000 ft.—Ben Lomond, 5,00o ft.; Mount Capoompeta, 5,loo ft.—sinks at either extrem ity to c. 4,00o ft.; Mount Lindsay (Macpherson Range), ft.; Oxley's Peak (Liverpool Range), 4,500 ft.—and has con siderable outliers, on the west the volcanic Nandewars (4,000 ft.) and Warrumbungle Range (3,00o ft.), and on the east and south the semi-detached spurs carved out by stream erosion into the likeness of ranges—Hastings, Mount Royal, Liverpool, etc., "Ranges." To the south of these ranges the plateau belt is broken across and the Central Plateau is separated from the more north erly by the remarkable Hunter River valley, the saddle at the head of which (near Cassilis) lies at c. 1,5oo ft. The Central Plateau extends from this gap to the Lake George depression just north of the Federal Capital Territory. In general it repeats the features of the New England Plateau (cf. volcanic outliers on the west : Canobolas group, c. 3,00o ft.) but it is smaller and lower, few areas rising above 4,00o ft., and altitudes vary considerably.

Its north-eastern section, the Blue Mountain Plateau, capped with (Triassic) sandstone, tilts from 4,00o ft. (west) to 700 ft. (east). From the Lake George fault-depression ("Senkungsfeld") to the border extends the Southern Plateau, a portion of the Australian Alps, a series of massive flattish-topped blocks diversified by (mainly north to south) down-faulted depressions (Mount, Kosciusko, 7,328 ft.). Geologically this highland belt is charac terised by its prevailingly ancient rocks (pre-Cambrian granites, folded Palaeozoics, etc.) ; by the volcanic flows (basalt, trachyte, etc.) which form cappings over considerable areas; by the exten sive faulting which has differentiated levels, dislocated former drainage and resulted, in particular, in the abrupt scarps and declivities of the eastern flank; by the flattening by erosion (peneplanation) of the surfaces.

(ii.) The Coastal Lowlands

belong structurally to the high land belt, being mainly, perhaps, down-faulted portions of it. The coast-line also appears in certain stretches (e.g., in the south) to be fault-determined. Almost everywhere the plateaux behind break away in sharp declivities and form steep backing walls often scarred by deep gorges. The coastal lowlands are mostly narrow (Io-2o miles)—often mere deltaic fringes at river-mouths. In three places—around Sydney, Hunter River, Clarence-Richmond Tweed rivers—they form roomier basins in which later rock formations (e.g., Triassic) have been preserved. The Hunter Goulburn Valley is a down-faulted trough worked out by erosion in weak strata and breaks across the highlands, running almost straight south-east to north-west for 120 miles to the Cassilis saddle (v. sup.) and is floored in its lower part with deltaic de posits. The structure of the Hunter Valley and of the Sydney Basin accounts for the outcropping of valuable coal seams. The coast-line, backed in many parts by bold heights, consists mainly of a succession of rugged promontories alternating with sandy bays and some inlets. In the central portion, on the other hand, subsidence has produced fine drowned valley harbours (Sydney, Port Stephens, Broken Bay, etc.).