The earthquake that occurred near Appin, New South Wales, on 15 November 1981 and its aftershock of 19 November were both associated with thrust faulting in the middle crust (10-20 km), caused by east-west compressive forces. The magnitudes of the main earthquake were estimated to be 3.9 Ms, 4.3 mb, 4.6 ML and 4.1 Mw, and a seismic moment of about 1.4 x 10^1 5 N-m was estimated. Although no damage was reported, the main earthquake was felt over about 60 000 km^2 of New South Wales, with a maximum felt intensity of 5 on the Modified Mercalli Scale experienced near the epicentral region and along the coastal plain from Wollongong to Nowra. The radius of the MMIV isoseismal was about 200 km.

Pollen and spore assemblages have been recovered from coaly lenses and marginal facies of Tertiary lacustrine sediments at Lake Bunyan, north of Cooma, southern New South Wales. Remains of lake sediments in the area are extensive , and a variety of facies has been recognised. Clays are dominant, but volcanogenic conglomerates, sands, silts , coals, diatomites , and a marginal quartzose facies also occur. Palynological assemblages have been recovered from coaly lenses and from the marginal facies. The pollen and spore suite is poorly diversified. Pollen of Nothofagus dominates, and that of podocarpaceous conifers is well represented. Myrtaceous pollen is common in a few samples only, proteaceous pollen is very rare , and there is occasional local dominance by aquatic taxa. Dating is made difficult by a lack of known stratigraphic marker species. In general, the assemblage resembles microfloras of the Proteacidites tuberculatus Zone, which spans the early Oligocene through early Miocene interval in the Gippsland Basin. The presence of Haloragacidites haloragoides, however, is more in accord with the Triporopollenites bellus Zone, of late early to late Miocene age. Detailed comparison with other palynological suites from highland sites dated by association with basalts suggests an age for the Lake Bunyan deposit of 12-21 m.y. , i.e. late early to middle Miocene. In comparison with other Miocene pollen floras from southeastern Australia , the Bunyan assemblage lacks forms indicative of subtropical rainforest, and forms indicative of cool temperate rainforest are poorly diversified. These features, combined with the relative abundance of conifer pollen in the assemblage, may reflect conditions somewhat cooler than other areas of southeastern Australia during the Miocene. An interpretation of pollen spectra from the deposit suggests that a variety of lake edge and bog communities successively surrounded the sites examined.

Six sedimentary cycles, each hundreds of metres thick, have been recognised in the Surat Basin. The Jurassic cycles (nos. 1-4) typically started with high-energy deposition of coarse sediments, and ended with labile sand, silt, and mud. The environments are thought to have been braided streams, followed by meandering streams, swamps, lakes, and deltas. After a period of non-deposition or erosion, followed by a phase of high-energy deposition, the first Cretaceous cycle (no. 5) ended with marine mud; the second (cycle 6) started with paralic silt and sand and ended with shallow marine silt. The cycles are thought to be the result of global sea-level changes, characterised by rapid falls of sea level followed by slow rises, which, respectively, lowered and raised the base of erosion in the Surat Basin. During the Jurassic, the open sea lay several hundred kilometres to the east, and the sea only occasionally entered the basin, via the Brisbane and Toowoomba Straits. In the Cretaceous, the sea level was relatively higher and eustatic falls and rises of sea level led to alternating marine regressions and transgressions. The six Surat Basin cycles correspond in time to nine global sea-level oscillations. We think that some of the latter may have been too slight to be identified in the basin. There is also evidence that local isostatic movements may have exaggerated the impact of some global cycles and obscured that of others.

The design and construction of safe and economic dams depends upon many factors, not least of which is an accurate assessment of the geology of the dam site and reservoir area. During the past 80 years, geological factors have caused the failure of, or serious damage to, at least 150 large dams throughout the world. Since 1945, ten possible sites for large water supply dams in the Canberra area have been geologically investigated; of these, three sites were selected for the design and construction of dams. In each case, the site selected, the type of dam constructed, and the layout of the engineering structures were decided upon only after detailed geological investigations. Geological mapping was carried out continuously during the construction of all three dams, and variations from the expected conditions were encountered at each site. Examples are given of problems caused by geological factors which arose at each site, together with the measures adopted to overcome the difficulties. Despite these problems, each of the dams was constructed at a cost very close to the original contract price, and no significant stability problems have occurred during their operation. The thorough geological investigations carried out at these sites have contributed significantly to the economic and safe construction of the three dams.

A new asterolepidoid antiarch is described from sediments of probable Late Devonian (Frasnian) age in the Boyd Volcanic Complex. on the south coast of New South Wales. It occurs as a rare element in an assumed freshwater assemblage wi th abundant Bothriolepis and Phyllolepis, and less common rhipidistian, acanthodian, and possible onychodontid remains. Pambulaspis cobandrahensis gen. et sp. nov. resembles Remigolepis in possessing separate posterior dorsolateral and lateral plates and a prominent postorbital crista, and resembles Asterolepis in having an elongate postorbital process and prominent subobstantic area, and lacking the posterior oblique pit-line groove in the adult. It differs from both in that the posterior dorsolateral completely overlaps the anterior median dorsal, and the lateral line canal crosses the posterior lateral plate instead of the posterior dorsolateral. The preorbital region of the skull , certain plates of the trunk, and the basic structure of the pectoral fin are not known. It is suggested that Pambulaspis is closely related to Asterolepis and Remigo/epis, and may be a sister taxon to the latter. The most recent common ancestor of these genera must have been Eifelian or older.

Eustatic changes in sea level can be used to correlate sequences in widely separated areas. Thick terrestrial sequences with marine intercalations are especially suitable, provided the marine beds are not the result of tectonic subsidence. The method has been used to correlate Late Permian coal measures in the Sydney, Gunnedah, and Bowen Basins. The Dempsey Formation and its equivalents in the Sydney Basin, an unnamed correlative in the Gunnedah Basin, and the Black Alley Shale and MacMillan Formation in the Bowen Basin have been identified as being deposited during the same eustatic highstand, a result consistent with palynological conclusions. The Kulnura Marine Tongue (Sydney Basin) and the lower Burngrove Formation (Bowen Basin), on the other hand, owe their origin to tectonism. The correlations indicate that deposition of Late Permian coal measures began in the Bowen Basin later than in the Sydney and Gunnedah Basins, a conclusion that appears to be supported by marine macrofossil studies.