Nature conservation

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North Coast - subregions

Subregions of the North Coast Bioregion
SubregionGeologyCharacteristic landformsTypical soilsVegetation
Murwillumbah Folded Devonian lithic sandstones, slate and phyllite. Small areas of loamy alluvium. Finely dissected steep ranges, with narrow alluvial plains. Relief to 250 m. Shallow yellow earths on hill crests, yellow and brown texture contrast profiles on slopes and organic loams on alluvial plains. Wet and dry sclerophyll forests, including blackbutt, Sydney blue gum, forest red gum on lower slopes and plains.
Richmond-Tweed Jurassic lithic and quartz sandstones and shales exposed in valleys. Tertiary volcanics of the Mt Warning complex. Mainly sheet basalts, with minor rhyolite and tuffs. Major syenite and gabbro plug - remnant of the caldera explosion. Dissected volcanic caldera with central plug of Mt Warning. Basement recks exposed around the plug and an outer rim of volcanic flows with well-developed radial drainage pattern. Steep slopes and relief of 1100 m. Red friable loams on basalts, texture contrast and fabric contrast soils on volcanic rocks on slopes, all with high fertility. Low fertility texture contrast soils on sandstones and shales. Cracking clays in valleys. Subtropical and warm temperate rainforests and wet sclerophyll forests including; black booyong, white booyong, hoop pine, bangalow palm, climbing palm, rough tree fern, Australian cedar, teak, white mahogany, small-fruited grey gum, tallowwood and Sydney blue gum.
Woodenbong Jurassic lithic and quartz sandstones, and shales with areas of Tertiary basalts. Hilly, basalt ridges and plateau remnants. Outer and dissected parts of Mt Warning caldera slopes. Relief to 600 m. Fertile red earths and red loams on basalt. Poor red, brown and yellow, texture contrast soils on sedimentary rocks. Sands and loams along streams. Rainforests on basalt as for Richmond-Tweed. Wet and dry sclerophyll, including New England blackbutt, red bloodwood and tallowwood on sedimentary rocks.
Clarence Basin Sub-horizontal Jurassic and Cretaceous lithic and quartz sandstones and claystones. Extensive areas of alluvials and coastal barrier sands. Low stepped hills and plains, with hillier areas in west and south. Beach, dune and lagoon barrier systems and estuarine fills along the main streams. Mellow texture contrast soils and areas of deep sand on Mesozoic rocks. Deep siliceous sands and podsols in dunes, organic sands and mud in estuaries. Dry sclerophyll forests and woodlands of spotted gum, grey gum, blackbutt, red bloodwood and white mahogany in the hills. Dune sequence includes paperbark, snappy gum, blackbutt, dwarf red bloodwood, bastard mahogany with banksia, bangalow palm and areas of heath and paperbark swamp. Mangroves in estuaries.
Nymboida Complex faulted bedrock of Devonian slates and quartzites, and Permian mudstones and lithic sandstones both intruded by granodiorites. Areas of Tertiary basalt on the margins of the Great Escarpment. Serpentinite at Baryulgil. Foothills of the Great Escarpment with steep slopes and high rainfall. Relief to 750 m. Some isolated plateaus often with a basalt cap. Red earths and red loams on basalts and granodiorites. Red and brown texture contrast soils on volcanics and sedimentary rocks. Dry sclerophyll forest, including northern grey ironbark, broad-leaved white mahogany, white mahogany, tallowwood and turpentine. Rainforest elements in sheltered locations along escarpment including coachwood, crabapple, prickly ash, and rough tree fern.
Manning-Macleay Extremely complex faulted terrain where the New England Fold belt over-thrusts the Sydney Basin. Main rocks present are: Silurian and Devonian slates, quartzites and acid volcanics, Carboniferous mudstones and lithic sandstones, and less deformed Permian shales and sandstones. Small areas of granite and plateaus of Tertiary basalt on Barrington and Comboyne Plateaus. Quaternary coastal sands. Complex pattern of ridges and valleys running to the Great Escarpment, strong structural control along fault lines. Coastal beach, dune and lagoon barrier systems reach their maximum development at Myall Lakes. Red brown structured loams on basalt. A range of other soil types relating to geology but poorly known. Deep siliceous sands and very well developed podsols in dunes, particularly the older high dunes. Organic sands in estuaries. Wet sclerophyll forest with white mahogany, small-fruited grey gum, Sydney blue gum, blackbutt, tallowwood and brush box. White gum, blackbutt, forest red gum and grey box on dry open flats. Dense Antarctic beech on Barrington tops and patches of mixed cool temperate and warm temperate rainforest on Comboyne Plateau on basalt. Coastal complex of banksia, paperbark, smooth-barked apple, and blackbutt with numerous shrubs and areas of heath and swamp on dunes. Mangroves in estuaries.
Southern Coastal Lowlands Quaternary alluvial sand, coastal sands. Minor Devonian slate, phyllite and quartzite. Alluvial plains and coastal beach, dune barrier system and estuary of the Tweed River. Low hills to 25 m. Siliceous sands and deep podsols in older dunes. Organic sands and muds along the streams and edges of the estuary. Mellow texture contrast soils on bedrock. Coastal heaths and woodlands on the dunes with paperbark, snappy gum, blackbutt, dwarf red bloodwood, bastard mahogany with banksia, bangalow palm and other shrubs. Areas of seasonally waterlogged heath and swamp. Swamp oak, paperbark and saltmarsh species with mangroves in estuaries. Flooded gum on alluvial flats.

From Morgan, 2001

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Page last updated: 18 April 2016