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The marine invertebrate macrofauna from the upper part of the Blenheim Subgroup of the Bowen Basin and the Kulnura Marine Tongue of the Sydney Basin is described. The fauna is assigned to 12 genera, one of which - Pseudonucula - is newly recognised, and to 13 species, of which one is new. On the basis of these descriptions and existing published information, three zones are recognised in the Blenheim subgroup, in ascending order, the Martiniopsis magna, the Martiniopsis pelicanensis and the Martiniopsis havilensis zones. An explanation is given of the conclusions of Waterhouse and Jell (1983) about the lower part of the subgroup. From the fauna, particularly the occurrence of Martiniopsis havilensis, it is concluded that a hiatus occurs in the Blenheim Subgroup between the Black Alley Shale and the Peawaddy Formation in the southwestern part of the Bowen Basin, and that the Black Alley Shale is equivalent to the MacMillan Formation in the central part of the basin and the Exmoor Formation in the northeastern part. The upper part of the Blenheim Subgroup (zone of Martiniopsis havilensis) seems to be younger than the Mulbring Shale of the Sydney Basin, and the Kulnura Tongue is not likely to be significantly younger than the Blenheim Subgroup. The faunas described appear to be younger than Kungurian, but are not likely to be younger than the Kazanian. They are rather low in diversity relative to older Permian faunas in the two basins, and this probably reflects the rather restricted marine conditions at the end of the open sea in the two basins.

Nine species of trilobites are recorded from three localities within a restricted stratigraphic interval near the base of the newly defined Kayrunnera Group (previously Kayrunnera Beds) on Kayrunnera station, western New South Wales. These occurrences come from the Boshy Formation of the Kayrunnera Group. The trilobites described include species of Ammagnostus, Meteoraspis, Biaverta, Blackwelderia, Bergeronites, and Placosema. This assemblage is early Late Cambrian (Mindyallan), and most closely referable to the late Mindyallan zone of Glyptagnostus stolidotus. The steeply dipping,weakly cleaved Upper Cambrian-basal Ordovician Kayrunnera Group overlies, with a well-defined angular unconformity, a more deformed tightly folded and strongly cleaved, graded, turbidite sandstone sequence. The turbidite succession is considered to be Early to Middle Cambrian, by lithological correlation with similar rocks containing sponge spicules and trace fossils elsewhere in the Wonominta Block. The upright isoclinal folds of this sequence and the angular unconformity were produced during a major orogenic phase, probably an early expression of the Delamerian Orogeny, in late Middle Cambrian time. After uplift and erosion there followed a period of early-middle Late Cambrian marine transgression, during which the lower part of the Kayrunnera Group was deposited. The beds include the trilobite-bearing Boshy Formation, of shallow marine origin.

Teleseismic travel time residuals for 43 seismic observatories and 6 networks of portable seismographs have been combined to produce a contour map of residuals for the Australian continent. Travel times to the shield regions of central and western Australia are low compared with average global travel times, indicating relatively high velocities in the upper mantle. The lowest times occur in the Archaean shield regions of Western Australia, the Proterozoic terranes in central Australia and the Gawler Block in South Australia, where heat flow is generally below world average. The residuals become progressively higher (arrival times later) towards the southeast, and the largest residuals are in Tasmania. The positive residuals indicate low velocities in the upper mantle, consistent with the predicted low velocity layer in the upper mantle under southeastern Australia, and higher observed heat flow.

Discussion: Ollier and Taylor (1988) are correct when they write that the Kosciusko- Bega region has long been of interest to geomorphologists, They also point out that there has been debate over its geomorphic evolution since the early 1900s and, after reviewing some of this, develop a hypothesis of landscape evolution for the area. We wish to examine the data underlying their hypothesis, and comment on other aspects of their paper.

The Murray Basin is one of the most important agricultural regions in Australia. After just 100 years of European development, salinity problems threaten the regional economy and natural environment of the basin. Some of the reasons for salinisation lie in the subsurface geology and geological history of the basin over the past 60 Ma. Knowledge of these is needed to understand hydrogeological systems and processes contributing to the development of present salinity problems, and why some natural sites are particularly susceptible to groundwater discharge and salinisation.

An overview is given of New South Wales saline seepage and resultant dryland salinisation, in the context of land degradation concerns across the Murray-Darling Basin. Causes of saline water discharge, the extent of dryland salting in the State, and its effects on land and water resources are outlined. The problem is assessed in terms of present knowledge and action needed to prevent and / or control its spread. Research priorities are suggested. Both specific and broad strategies already addressing dryland salinisation and associated land degradation are described. Future actions for New South Wales are outlined and the need is stressed for community education, as well as 3-way cooperation between governments, scientists and landholders.

Available data about recharge from irrigation areas in the Mallee and Riverine Plains zones of the Murray-Darling Basin are reviewed. The need for clear understanding of how data have been obtained and care in their use, and the need to clearly identify the aquifer which is being recharged and to specify appropriate time and space scales are emphasised. The usefulness of the data for numerical modelling is discussed. Available data are considered adequate for establishing regional priorities for action to reduce recharge. However, site-specific data are required for design of projects at the local or sub-regional scale. Monitoring of system performance during and after implementation is necessary to verify the accuracy of data used. Options available for recharge reduction are discussed. Recharge rates in the Mallee zone are very high, and significant reductions can readily be achieved. Many irrigated areas in the Mallee zone are already tile drained, so the main benefits of recharge reduction will be lower regional water tables and reduced groundwater discharge to the River Murray. Recharge rates in the Riverine Plains zone are generally much lower, although some areas of high recharge do occur. Options for recharge reduction are identified for use in appropriate circumstances, but it is considered that residual recharge rates are likely to exceed the safe discharge capacity of the underlying acquifers. Subsurface drainage of the more intensively irrigated areas will be required (as in the Mallee zone), to avoid significant losses of production and land degradation.

Widespread clearing of native vegetation has dramatically increased recharge in the Mallee region by up to two orders of magnitude. The resultant rising water tables have caused land salinisation problems in low lying areas and, in the long term, will increase saline groundwater inflows to the River Murray with a consequent rise in river salinity. Computer modelling suggests that, 50 years after the water table begins responding to the increase in recharge, an increase of 70 Electrical Conductivity (EC) units in river salinity will occur at Morgan. Broadscale revegetation in strategic areas adjacent to the river will reduce saline groundwater inflows, and the economic and social aspects of this measure should be investigated.

In the Murray-Darling Basin, agricultural production (from cropland and irrigated agriculture) foregone through land degradation is estimated at $214.6 million/year. Clearing and the replacement of deep-rooted native vegetation by shallow-rooted annuals have been identified as major causes of increased groundwater recharge and land and water degradation. Improved vegetation management and revegetation of degraded and degrading lands will lead to significant improvements in surface water quality. Proposed actions under the Murray-Darling Basin Ministerial Council Draft Vegetation Management Strategy include clearing and development controls, management of degraded and degrading lands, assistance and incentive measures, and improved community awareness and education. Recharge strategies (preventative measures aimed at reducing deep percolation to the groundwater over large areas of land, by the increased and more efficient use of soil water supplied by rainfall) include reforestation and agroforestry, agronomic and engineering strategies. Economic benefits of agroforestry are frequently overestimated. Current arrangements for marketing commercial timber, setting prices, and levying taxes discourage private tree plantings, as do a lack of labour and management skills, the relative profitability of alternatives, and availability of capital. Though there are apparent benefits from forestry-based activities, which simultaneously control groundwater levels and dryland salinity, farmers need incentives to move to forestry-based systems. Most research predicts a net social gain from reduction in salinity problems, but the importance of water yield has been neglected. The importance of model specification to the selection of appropriate land use is also emphasised. It is concluded that broadscale revegetation using tree-based systems is not economic or practical as a groundwater and salinity management tool but should be evaluated in terms of local conditions. In addition, vegetation management should be more widely interpreted to include all vegetation which may be used to control groundwater and salinity.