Latitude -33.087838, Longitude 151.665144
Located in the Hunter Region of NSW, nearest town Swansea
Source: Field geology of New South Wales
Swansea Heads are located at the mouth of Lake Macquarie, the largest coastal lake in Australia. The Awabakal aboriginal people are the traditional owners of this land and the coastal platform provided plenty of resources for them. In the years after colonisation there was much activity in the Hunter Valley, early sighting of many coal seams outcropping on the coastal headlands led to exploration and mining and Newcastle produced the first coal for export in 1801. (see document featuring Glenrock SRA on this website). The southern headland at Swansea is called Reids Mistake after a collier captain in 1800 mistook the entrance to Lake Macquarie for that of the Hunter River at Newcastle. He was able to get a load of coal in any case so the mistake wasn't costly.
Park your car in the car park at Reids Mistake Reserve. From there it is s short walk to the rock platform; It is best to go at low tide for obvious reasons.
The platform consists of tuff which overlays the Lower Pilot Seam. The headland has excellent exposures of the Boolaroo Formation including the Lower and Upper Pilot Seam and cherty tuffs.
The fossil tree stumps are common on the platform and appear to be situated in their original location with some fallen logs remained partly attached to stumps in a growth position. The fallen trees have a mutual orientation leaning towards the west. This has lead to the belief that the forest was overcome by a volcanic eruption some 20km to the east that covered the trees with volcanic ash (tuff). Charred wood and stripped bark occur on the outer surfaces of some stumps and some of the stumps are coalified.
If you have seen footage of the (www.youtube.com/watch?v=xP2dreOI8gI) Mount St. Helens eruption in 1980 you will be familiar with the force of the shockwave which laid forests on their sides radiating out from the blast. Similar to Mount St Helens, at Reids Mistake fossil site the expulsion of hot pyroclastic material snapped off the trees and tilted the stumps towards the west and aligned the trunks east west. Ash would then have settled on the tree stumps and flattened branches, and over time this ash would have lithified into tuff.
The remnant forest comprises ancient Glossopteris trees which have been fossilised for some 250 million years. There are many leaf fossils in fine laminated (indicates ash-fall) grey tuff scattered about the rock platform. One fossil stump that is situated in the lower coal seam has its root system still quite visible indicating that the trees were the source of the coal deposits.
If you look at the headland behind the rock platform you will see two coal seams - the lower one, Reid's Mistake Formation and the higher one Upper Pilot Seam. The Lower Pilot Seam is in the rock platform below your feet. Further south along the cliff, massive conglomerates with sandstone layers belonging to the Belmont Conglomerate Member appear.
Swansea is located on the Hunter Valley coast at the Lake Macquarie ocean entrance. Reids Mistake is the southern headland of the lake entrance. Access the area via the Pacific Highway at the large round-about at the southern end of Swansea. Here turn east into Bowman St, then turn left into Northcote Ave, then left into Hamilton St and then right into Lambton Parade and follow to the end and park at Reids Reserve carpark. A nearby path leads to the rock platform. Make sure you go when the tide is low.
Allow 1.5 hours to examine the petrified forest and rock platform. Make sure you take a hat and sunscreen.