Shoalhaven District Geology

  FIELD GEOLOGY OF THE SHOALHAVEN DISTRICT (PART 19) Chapter 11   Tianjara and the Little Forest Plateau     Among the landmarks of the Shoalhaven district is the  Tianjara  group of mesas. They lie about 5 miles south of the Braidwood road, near Tianjara Falls. Their flat surfaces, bounded by cliffs and steep slopes make them obvious from all directions, but particularly from the north. They are easily visible from Bundanoon, Saddleback, and Durras Mountain.  Extensive outliers of the Berry Formation cap the coastal hills south from Tianjara Falls to the Little Forest Plateau. This is uninhabited country, used as a military practice area and out of bounds from time to time. The sediments of the Berry Formation are rather coarser than those further north. The presence of the mesas may be due to the peculiar resistance of the strata in this area. Some geographers have suggested that they may be relics of a former land surface, uplifted and lar...

FIELD GEOLOGY OF THE SHOALHAVEN DISTRICT (PART 16) Chapter 9 continued.  Excursion 9b Touga, Tolwong, and the Ettrema Gorge   (70 miles return) The spectacular scenery of this country has been explained earlier. Most of the features of geological interest are to be found in the older rocks, beneath the Permian cover. This is the most mineralised area in the Shoalhaven district and one suspects that great mineral wealth lies undetected beneath hundreds of feet of Permian sandstone. Route:  Sassafras-Touga-Quiera-Tolwong Leave the Braidwood road about 5 miles past Sassafras and 1.3 miles before the descent to the Endrick River. The road passes over sandstone of the Berry Formation for about 3 miles and then over the Nowra Sandstone at a place locally called ‘ The Jumps ’. The narrow ridge along which the road passes is besieged on both sides by deep valleys, which at this point have eaten away a large part of the sandstone. This road is part of a route used by bullock teams...

  FIELD GEOLOGY OF THE SHOALHAVEN DISTRICT (PART 15) Ettrema and Beyond – the Great Gorges. Excursion 9a One must never underestimate the erosive power of running water. Almost as fast as the uplifting process begins, many streams large and small begin to level the land again. Nowhere is this better seen than in the gorge country west of Nowra, where scrubby sandstone plateaux give way to great canyons, and tinkling waterfalls demonstrate the ceaseless battle between the two. Ettrema Gorge January 1969 From sea level at Nowra, the sandstone surface rises, almost imperceptibly, to a height of 2,500 feet in the west. The Shoalhaven River and its tributaries have removed this resistant layer along their courses and exposed the older rocks below. Unlike Kangaroo Valley, these gorges have little to attract the settler since their few level areas are comparatively infertile and access is difficult indeed. It has taken the discovery of minerals – gold, silver, and lead – to cause man to d...

  FIELD GEOLOGY OF THE SHOALHAVEN DISTRICT (PART 11) Chapter 6  The Yalwal and Burrier Districts   Scattered throughout Australia are numerous ghost towns. Yalwal is such a place, but time has removed all but a trace of the town itself and left only the mines which once brought prosperity.  That famous cleric-cum-geologist, the Rev. WB Clarke, noted the existence of gold here as early as 1852. He reported that fine gold was to be found in Danjera and Yalwal Creeks, recommending further prospecting to the local settlers. The ‘golden era’ began in 1872 and lasted into the present century, with minor revivals ever since.  The Permian strata rise gradually to the west, exposing the basement rocks in all valleys west of Grassy Gully. The oldest strata are comparable to those known to be of Ordovician age and consist of altered clastic sediments. These are exposed only in parts of Danjera and Yarramunmun Creeks. They are overlain by sandstones and conglomerate, contai...