A very long time ago, on 4 February 2007 to be precise, The Macleay Valley - the glacial age, provided an initial introduction to the paleogeography of New England. Since then, I have done bits and pieces, but still do not have a clear picture firmly fixed in my mind.
In October this year, Rod began his blog on Northern Rivers Geology. I asked Rod whether he would write something on change over the last 50,000 years. He has promised to do so in due course.
50,000 years is an important span from my perspective because it presently represents the maximum period of Aboriginal occupation of New England. The earliest accepted date we presently have for a location just to the north of New England is some 20,000 years ago. My feeling is that occupation probably began earlier.
History is about dialogue, dialogue with our sources, dialogue with those interested. To encourage Rod and to extend dialogue, I have decided to post some of my own notes on New England's paleogeography as my contribution to discussion.
Aboriginal New England in the Pleistocene Period
Aboriginal people may have reached the area that would be variously called Northern New South Wales, the North, Northern Districts or New England as early as 40,000 years ago.
We know from dating at Warren Cave in Tasmania that the Aborigines had reached Tasmania around 35,000 years ago while dates from Willandra Lakes in South West New South Wales suggest occupation as early as 41-40,000 years ago. Given these dates, it seems reasonable to assume a working date of around 40,000 years ago for first Aboriginal occupation of New England.
We do not have hard evidence for this dates. The earliest confirmed date I know of in New England itself comes from a dig by Graham Connor at Stuarts Point in the Macleay Valley. This places human occupation at 9,320 +/- 160BP. Further north in South-East Queensland, the Wallen Wallen Creek site shows continuous occupation from about 20,000 years ago.
The Cuddie Springs site near Brewarrina is especially interesting because it suggests occupation as long ago as 35,000 years BP. However, dates here have been subject to considerable dispute and there presently appears to be no agreement on the issue.
Despite the absence of earlier dates, it is hard to believe that the Aborigines had not reached New England if they were at Willandra Lakes around 40,000 years ago, had reached the southwest of what is now Tasmania by at least 35,000 years ago.
What type of world did they find?
Sea levels fluctuated greatly during the long Pleistocene period. Forty thousand years ago, sea levels were perhaps 50 metres below current levels, creating a broader coastal plain. Rainfall was high, temperatures moderate. Rivers running east and west from the Tablelands would have carried substantial volumes of water.
In the east, the river estuaries and wetlands as we know them today did not exist, nor did bays and harbours such as Trial Bay or Port Stephens. The present sea bed drops reasonably sharply in spots, so there would probably have been a significant gradient towards the sea with current headlands standing out as hills or ridges.
The significant volumes of water carried in the eastern flowing streams would have led to some progradation pushing the land out into the sea. With time, this would have led to river estuaries, coastal dunes and marshes. It seems likely that the larger coastal strip was thickly wooded and reasonably rich in marine and land resources.
In the west, the rivers and associated wet lands would also have provided a rich environment., although probably not as rich as it was to become.
The position on the Tablelands is unclear because so much of the analysis that I have seen deals with later periods. I suspect that the Tablelands were wooded and at least visited by surrounding groups.
The size and distribution of the early Aboriginal population is obviously unknown since at this stage we have yet to prove that they even existed. My own feeling is that it was probably much smaller but mirrored the pattern at the time the Europeans arrived; higher concentrations on the coast and on the western slopes and immediate plains, sparse on the Tablelands.
From around 36,000 years ago, the climate became cooler and drier. The cooler temperatures offset the lower rainfall by reduced evaporation; the streams, lakes and wetlands of inland New England therefore retained their water, providing a continued base for Aboriginal occupation.
From perhaps 25,000 years ago, the local environment deteriorated significantly. Sahul, the name given to the continent that then included Australia and New Guinea, became very dry, both intensely hot and intensely cold. This climatic regime peaked during what is called the Last Glacial Maximum, 21,000 to 15,000 years ago.
The sea retreated to perhaps 120 metres below current levels. The sea became colder, 2-4 degrees C below current levels. On land, mean monthly temperatures probably fell by 6-10 degrees C. Extensive inland dune building suggests that the climate become much windier.
According to Mulvaney and Kamminga, severe cold, drought, and strong winds over central and southern Sahul, would have discouraged tree growth , although some species common today must have survived in sheltered or better-watered refuges.
The retreating sea would have progressively increased the size of New England’s coastal strip. The impact here would have varied along the coast, depending upon water depth. In broad terms, the immediately adjacent shallow water to the east of the present coast is quite narrow, with the continental shelf then falling away sharply.
In South East Queensland to the north, the falling waters probably extended the coastal strip to between twelve and twenty kilometres east from what is now Stradbroke Island. Further south the lower water zone narrows, before widening a little after what is now Nambucca. In the case of what is now the Macleay Valley, the coast line probably extended ten to sixteen kilometres to the east.
The sclerophyll woodland and deciduous forests would have progressively colonised the new land, with the coastal dunes and associated wetlands following the shifting coast east.
The Tablelands would have been a very different story. Here average temperatures fell by perhaps 8 degrees C. The New England Tablelands marked the start of a region of cold steppe and scattered sub-alpine woodland sweeping down through the southern Snowy Mountains into Tasmania.
In the southern Snowy Mountains, the fall in temperature was sufficient to allow glaciers to form despite the lower precipitation. In New England, the higher portions of the Tablelands in the centre and south where average heights are around 1,300 metres must have been very cold, dry and windswept. Along New England’s Snowy Mountains where the highest peak (Round Mountain) is almost 1,600 metres, there were probably blizzards and semi-permanent snow despite the much lower precipitation.
To the west, Mulvaney and Kamminga suggest that much of the south-eastern interior of Sahul experienced cold arid conditions similar to modern Patagonia.
Josphine Flood notes that the pollen record for Cuddie Springs on the Western Plains shows decreasing tree, shrub and grass cover with a rise in saltbush (Chenopodiaceae) suggesting growing aridity as the as the glacial maximum approached. She suggests that the environmental record for Ulunga Springs, 180 kilometres southeast of Cuddie Springs, shows a similar pattern between 30,000 to 10,000 BP. The net effect was an expansion of the continent’s arid core by at least 150 kilometres.
That said, the lower western Tablelands and slopes were probably vegetated by grassland with spring herbs with patches of woodland and forests. Further west, the streams crossed the arid plains.
While these changes took millennia and would not have been noticeable to individual generations, the effect on the human population must have been quite severe.
Water and food supply were two of the critical determinants of prehistoric demography. Water became scarcer, droughts more frequent. Food supply was reduced. Over time, populations would have been forced to relocate and may well have become much smaller.
In the absence of archaeological evidence, it is impossible to say just what the precise effects were in New England. While colder and drier, there would have been sufficient water and food resources to maintain populations
We know that there was Aboriginal occupation of the coastal strip given that the Wallen Wallen site in South East Queensland shows continuous occupation from 20,000 years ago, a date in the earlier part the Late Glacial Maximum. It is reasonable to assume that any occupation on at least the majority of the Tablelands ceased. But what happened further west?
Under current climate, Northern NSW is generally wetter and warmer than Southern NSW because the area is affected by two different weather patterns. Rainfall also declines to the west because of the impact of the Eastern Ranges.
The climate during the Late Glacial Maximum was clearly very different. However, my feeling is that the current pattern was replicated to some extent because of air flows from what is now the Pacific.
In later times, ethno-historical evidence suggests that the presence of standing water was very important. During wet periods, people moved out into the broader landscape, concentrating round permanent water during dry periods.
With diminished rainfall but also lower temperatures, it seems likely that there were areas on the Western Slopes and Plains that would have continued to provide sufficient water and food to maintain life. Why, then, is there still no archaeological record? It seems likely that any previous human occupation of the Tablelands would have come to an end, although people may still have visited the lower areas.
Assuming that the area was populated, the pattern of sites would have reflected then on-ground conditions. Many of the sites would have been camping sites, not easily identifiable beyond lithic scatter. Other sites would have reflected the then location of permanent water.
My feeling is that we need to chart what the landscape was like then to identify possible sites. Mind you, this may already have been done and I have simply not discovered the analysis.
 John Mulvaney & Johan Kamminga, Prehistory of Australia, Allen & Unwin, Crows Nest, 1999. P186. The broad framework for this section is drawn especially from Mulvaney & Kamminga’s work.
 Munvaney & Kamminga, op cit, p197. There is debate about the Wilandra Lakes dates, with some arguing for older dates. Josephine Flood, Archaeology of the Dreamtime, J.B. Publishing, Marleston, revised edition, 2004, p1.
 G Connah, Archaeology at the University of New England 1975-76, Australian Archaeology, No 5, 1976, PP1-5.
 Josephine Flood, Archaeology of the Dreamtime, J.B. Publishing, Marleston, revised edition, 2004, p189.
 The analysis here is based on an assessment of the present coastal boating maps accessed 15 April 2009. A full assessment would require analysis of broader maps indicating varying depths of the sea bottom, allowing a better assessment to be made of the outer coastal strip..
 Mulvaney & Kamminga, op cit, p116
 Flood, op cit, p113
 I have used the term southern Snowy Mountains because New England has its own smaller range also called the Snowy Mountains.
 Mulvaney & Kamminga, op cit, p117
 Flood, op cit, p192. .
 J Belshaw Population distribution and the pattern of seasonal movement in northern New South Wales. In I. McBryde (ed.), Records of Times Past, pp.65-81. Canberra: Australian Institute of Aboriginal Studies, 1978