HIDDEN deep in bush and backyards in the upper Blue Mountains west of Sydney are up to nine large, mysterious pits.
Their exact age or purpose is unknown, but they may well date back to the convict era.
Five of these pits are located around Blackheath, where the neatly excavated holes lie on the western side of the railway line between Medlow Bath and Mount Boyce.
The general belief is that they could be at least 170 years old. Some appear virtually unaltered except for eroded edges, but all once required a lot of work, most being dug through hard-packed soil. One, though, has vertical walls cut through sandstone.
Many Blackheath locals believe the strange holes, measuring about three metres wide, up to 3.8 metres long and up to six metres deep, could date back to the pioneering convict road builders in 1814, or more likely, later iron gangs, maintaining the road in the 1830s.
Various uses have been suggested for the mystery pits, but no one theory, except that they might be convict "punishment pits", seems to satisfy most people's curiosity.
One empty, hidden pit in Blackheath bush is now covered with reinforced steel mesh laid over three steel pipes, while others are almost filled in to eliminate dangers to pets, bushwalkers and firefighters alike.
Conjecture over the use of the pits varies from long-term food or water storage, animal traps, short-term cool storage of meat for railway workers and water storage for locomotives during construction of the rail line alongside the road in 1867-1868.
It's also been suggested the pits might have been used for shallow exploratory mineral mining, or maybe to store gunpowder. In theory at least this has merit, as storing explosives away from thieves had the added advantage of low pit temperatures maintaining stability.
The amount of water retained in some pits from runoff, however, works against this theory for most people.
Blue Mountains residents still doggedly refer to the sites as "convict pits", "isolation cells" or "convict holes".
The pits run close to the original route of William Cox's stony road, hacked over the mountain ridges from Emu Plains amid rain, severe cold and swirling mists in the winter of 1814.
The noisy Great Western Highway still roughly follows Cox's road, which in turn followed in the footsteps of the intrepid three explorers Blaxland, Lawson and Wentworth, the first Europeans to successfully cross the mountain barrier in 1813 to open up the vast western grass plains to Bathurst.
Because of increasing road traffic, a lot of Cox's rough, early road along the ridges was improved from 1822 by former Newcastle prison camp commandant Lieutenant William Lawson, then commandant at Bathurst, who followed in his own pioneering footsteps of nine years before.
Then in the 1830s and 1840s, up to 300 convicts in iron gangs maintained the colony's vital route to the west, based at stockades such as The Pass (Mount Victoria) where mammoth earthworks were constructed.
For Blue Mountains paranormal investigator "Paranormal" Pete Clifford, one thing is certain. That's the knowledge that the "scariest" place on the mountains today is "the pits"; two remote convict pits/wells about 400 metres off the road between Mount Victoria and nearby Mount York.
According to local legend, the most feisty convicts were once lowered by rope into these deep pits in the ground overnight to stop them escaping.
Many convicts who died while labouring on the road were buried in unmarked graves without any religious ceremony and some believe their souls still haunt the bush.
Clifford said he was left shaking one night after entering the dark bush at the pits where he claimed a ghost passed through him, screaming at him to "get out".
He said these "dark entities" made tourists uneasy on the weekend Blue Mountains Ghost Tours he's run since 2002.
"We've had psychics with our group at these convict wells who stay on the bus and refuse to get out," Clifford said.
He said many of the convicts working on Cox's road were Irish Catholic and without official funeral rites their tormented souls might still be in limbo.
"I discovered the pits years ago as a kid while trailbiking in the bush. I don't go to the Blackheath sites on the tours now, though, as I came back there once afterwards and found some people holding a se{aac}ance," he said.
Blue Mountains historian John Low said the number of convicts who lie buried in unmarked mountain graves was guesswork.
"People are still struggling for any information, they just want more evidence of this period," he said.
"A lot of folklore comes from the truth, but then it gets exaggerated along the way to us today. These pits anyway seem unlikely to be 'convict holes' from Cox's original road builders in 1814 because those [28] men were road building for their freedom. They wore no leg irons.
"And take the so-called convict graves off the highway at Pulpit Hill [above the famed Explorers Tree near Katoomba]. Estimates range from five to 10 to 20 graves being there. The RTA then did a ground-penetrating radar study on site but only found one grave. Shallow graves, however, may not have left any mark," Low said.
Blue Mountains Historical Society president Dr Peter Rickwood said later that despite years of research, the exact role of Blackheath's five pits and others remained unknown.
"And more pits are still being discovered. But they're nowhere near the railway line or road. It's very peculiar," he said.
"One mystery pit off Station Street, Blackheath, was filled in as a former home owner there was worried a child might fall in it. Firemen also have to be careful in other places while fighting fires.
"These pits are beautifully constructed and a lot of work has obviously gone into them, but we still have no definite explanation of why.
"Some 170 years later we can only speculate." a