Glenrock Lagoon Latitude -32.962514, Longitude 151.734409
Fossilised forest Latitude -32.987347, Longitude 151.729801
Located in the Hunter Valley Region of NSW, nearest large town Merewether
Glenrock State Recreation Area (SRA), besides being a beautiful landscape is a significant heritage and geological site. Its features include: evidence of long term aboriginal occupation by the Awabakal People, possible first coal discovery in the Hunter Valley, 19th Century coal mining, copper smelting, early industrial rail hauling of coal and silica, 1950s gravel quarries and evidence of long term decimation of natural environmental habitats. Plus the entire formation of the lower Newcastle coal measures. If that is not enough there is also the remains of a fossilised forest on Dudley Beach rock platform and evidence of volcanic activity indicated by the presence of indurated tuff rock on the headlands.
The SRA is centred on the Glenrock Lagoon, an important site for the Awabakal People, as it supplied a wide range of different Aboriginal food resources and collection areas including sandy and rocky platform foreshore, lagoon, forested hills, and creeks. The Awabakal People also exploited the local geological resources, including coal, red ochre and an exceptional exposure of indurated tuff, the highest grade tool-making stone located in the sea cliff at Glenrock Lagoon.
Before you visit this site remember that these fossils (and everything in the SRA) are protected by law and any kind of desecration carries strong penalties. Bear in mind that the fossils come from the Permian Era and are around 250 million years old, they were here before the dinosaurs.
To visit the fossil trees proceed to the southern end of Dudley then to the end of Goulburn Street, and follow the track to the beach. Just to the north, on the rock platform, there are many fossilised tree stumps, with numerous fallen trunks and branches. They are being eroded out of the host rock by the action of the sea. Visit at low tide and when the ocean is calm to ensure your safety. Depending on currents these fossils may be covered by sand and not visible at all.
Look for growth rings and bark in red-brown stump-like rocks embedded in the rock platform. The darker rock is limonite, a secondary mineral which would have filled the microscopic voids in the tree's tissues as they decayed replacing wood with mineral. Also observe smaller trees that have fallen before becoming fossilised. There is no strongly preferred orientation so they have not been flattened by a strong volcanic blast but in the Newcastle coal measures between Sydney and Newcastle volcanic ash falls appear to be the major cause of fossil forest preservation.
If walking from Merewether Baths, you may be lucky to see nearby another group of fossilised tree sections which are up to around 90cm across. These sections of trees can only be seen at low tide.
According to the Glenrock SRA management plan document the rock platform contains fossilised tree trunks embedded in the course sandstone over the Victoria coal seam.
Adjacent to these fossilised remains is an infant blow-hole in the rock platform
The SRA has high geodiversity, demonstrating through a variety of features the continuous geological development of the Sydney Basin over the course of 250 million years to the present.
The SRA contains the entire formation of the lower Newcastle Coal Measures. These are the formations, laid down in the Permian period, which underlie the younger Triassic sediments of the Sydney Basin. Their uplift and cross-sectional exposure by marine erosion have revealed them to spectacular effect along the beaches of the SRA.
The Newcastle Coal Measures comprises eight separate seams, seven of which are exposed at various locations within the reserve. The lower seams are exposed on the Merewether cliff face, a headland on the northern end of the SRA. The strata dip generally to the south. The changes in the elevation of the coal seams and their intervening Permian sediments relative to sea level along this dip are apparent on cliffs at Little Redhead Point and the Dudley headland. The Permian sediments which separate the coal seams include fossil-bearing shales as well as conglomerates, sandstones and cherts (tuffs) indicating regional volcanic activity.
The geomorphology of the area is similarly diverse. In particular, the ancient coastal lagoons at Glenrock Lagoon and Murdering Gully show different stages in the aging of these features. Glenrock Lagoon was formed by the Quaternary Era rise in sea level and was then closed by the accumulation of marine sand deposits at its mouth. Murdering Gully exhibits the next stage of maturation where a combination of wind-blown (aeolian) sands and sedimentation reclaims the lagoon and establishes a terrestrial surface much younger than its neighbours. Recent sedimentation studies of Glenrock Lagoon show that it is headed in this same direction (Peady 1991).
Another notable geomorphological feature is where the armouring effect of the conglomerates has protected the large rock-platform "flags" of Flaggy and Little Flaggy Creeks from weathering to produce the waterfalls and caverns which characterise these waterways.
Geomorphological processes in the SRA are ongoing - especially coastal processes. While not a receding coastline, the foreshores of the SRA will continue to be eroded by wind and waves. The softness of the sediments of the Newcastle coal measures will ensure that cliffs are periodically undercut and the cliff face will change. Ludwig Leichhardt, walking along the foreshore in 1842, noted a very recent rock fall at Dudley headland adjacent to the petrified trees. This rock fall is now a "permanent" feature of the rock platform.
The notes and letters of explorer and naturalist Ludwig Leichhardt visiting the area in the 1840s documented significant changes to vegetation preceding his visits. The cabbage tree palms (Livistonia australis), once so numerous that the upper Glenrock Lagoon and lower Flaggy Creek area was called Valley of Palms, had all but disappeared. Now there are no cabbage tree palms left which could indicate the effect of European settlement and mining.
Glenrock has long been associated with the first discovery of coal in Australia by William and Mary Bryant in 1791, a family of escaped convicts. Opinions differ on the likelihood that it was the coal seam at the mouth of the Glenrock Lagoon which they encountered and the exact location of the Bryant's discovery will probably never be known.
Coal mining is a significant theme in the history of New South Wales as a whole. NSW has produced the majority of Australia's coal and Newcastle produced the first coal for export in 1801 (Pearson and McGowan 2000:123). The coal mining remains at Glenrock derive from the third phase of coal mining in the Newcastle region: the first being government controlled mining using convict labour; the second phase from 1831 - 1847 was the Australian Agricultural Company's monopoly. The third phase, after 1847 is the opening up of this industry to private concerns.
The establishment of mining and smelting at Glenrock from the 1840s has shaped the cultural landscape and the theme of industry dominates the 19th century history of the place. The Glenrock coal mining remains include areas which were mined from the 1850s, while the coastal railway which first served them was begun in 1846. The most substantial colliery remains in Glenrock are found at the Burwood Colliery site. These remains relate to the 1880s Burwood Colliery but the variety of construction techniques observed in the ruins suggests that they may incorporate remains from a previous 1860s mine. This makes the Burwood Colliery remains amongst the oldest extant colliery remains in the Hunter (pers.com. Ed Tonks and David Wells).
Dr James Mitchell purchased most of the land around Glenrock in 1835. Mitchell was a Peninsular War veteran who used his contacts and scientific background to further his industrial ambitions. Mitchell was instrumental in forcing the Australian Agricultural Co. to relinquish its monopoly over coal production, through his establishment of Glenrock's coastal railway and the Burwood Copper Smelter. Mitchell's son was D. S. Mitchell (1836-1907) who established the huge collection of Australiana, upon which the Mitchell Library is based, through the profits from estates amassed by his father.
The Yuelarbah Track , (Awabakal Aboriginal language meaning "footsteps in the sand") is part of the Great North Walk. It is in good condition, blends well with the landscape and is well graded for the average walker. You will find the track head at the main car park on Burwood Road, Kahibah. A larger car park is located at Dudley Beach accessed from Dudley Beach Road, off Burwood Rd at Dudley. The walking track to Burwood (Smelters) Beach is from the southern side of Merewether Baths