Australia is an ancient continent.  It looks obvious enough when you head out west or into the northern deserts.  Not so obvious when you stand in the middle of the city or drive on the motorway towards Prospect and the Mountains.  But it is an old place, Sydney, and its geology and geography, formed over millions of years had a significant impact on the way the place was settled by Aboriginal people and much, much later by Europeans.

Sydney is coastal and has been for about 45 million years when the ancient Gondwana supercontinent began to break up and drift apart.  Bye bye New Zealand.  The break-up unleashed deep forces in the earth: a period of volcanic activity along the east coast of Australia exploded into action, including in the Sydney area around Prospect.  The eroded remnant of the volcanic core forms Prospect Hill, worn down over millions of years to a small nub in the otherwise flat lands of western Sydney. 

The pressure pushed up the sandstone in the west, forming the Blue Mountains and turning the previously western running rivers back on themselves.  Now heading east towards the distant seas, these new rivers carved great valleys out of the sandstone country, which finally formed the valley that is now Sydney Harbour and Pittwater.

At the time though it was a valley; probably quite lush, before transforming into the classic Sydney forest of tall blue gums and cabbage palms with a thick understorey of ferns and bracken.  This is about 20 million years ago or so. 

Humans arrive around 30-40,000 years ago, taking advantage of the valley to escape the desperate cold of the final ice age (so far) that was gripping the world. 

Although the area was coastal, it was a fair walk to the beach during this time.  The sea levels were considerably lower and the beach was about 30kms further east then Bondi is now.  Not sure I would walk 30kms to have a swim, especially in an ice age.

When Europeans turned up in 1788 things had changed.  The ice had long melted and the sea pushed inland through the old valleys, filling them up to form Sydney Harbour, Botany Bay and Pittwater.  Interestingly, even if they didn’t realise it, the Europeans were influenced by the ancient land.  They wanted good farm land and one of the first places they found was around Prospect Hill, the soil enriched by the eroded volcanic outpourings.  The land they didn’t like, such as the scrubby heathland to the south, the rugged forests to the west and the gorges to the north were left largely untouched.  These survived on the whole as Sydney’s big three National Parks, the Royal, The Blue Mountains and Ku-ring-gai.

And as for the volcano, it moved on, heading south where it is currently sitting dormant somewhere under Bass Straight.

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