There's one question that leaves Dr John Sherwood lying awake at night.
Does the shell deposit at Warrnambool's Moyjil site, also known as Point Ritchie, dated at close to 120,000 years old, have a human origin?
Because if it does, it re-writes the history of habitation on the planet as it would demonstrate Australia's Indigenous peoples were living among mega fauna about 60,000 years earlier than the currently accepted date of arrival of people on the continent.
Moyjil, about 10 minutes' drive from the coastal city's main drag, contains the remains of shellfish, crabs and fish in cemented sand, together with charcoal, blackened stones and features which resemble fireplaces.
The site has been the focus of intense scrutiny since 2008, resulting in a series of papers published by Dr Sherwood and other researchers in the Proceedings of the Royal Society of Victoria in March.
The team has aimed to test the hypothesis of a human origin for the site, but absolute proof has remained out of reach without the discovery of material such as a stone artefact or human remains.
"Will it ever get solved?" Dr Sherwood asks over coffee.
He said it was a "major relief" to publish the series of papers in March.
And since then one of the team's researchers, Professor Ian McNiven of Monash University's Indigenous Studies Centre and the ARC Centre of Excellence for Australian Biodiversity and Heritage, has been looking into whether fire at the site was caused naturally or by humans.
But his burning question remained unanswerable with the research tools presently at hand.
"It's very frustrating," Dr Sherwood said.
"We've worked as hard and as cautiously as possible and we've been very respectful of the site, so there haven't been major excavations to dig it up."
But Dr Sherwood hopes to present a paper at the Australian Archaeological Association conference on the Gold Coast in December in a bid to put the research in front of a national audience and trigger feedback.
"I'm optimistic we might get a solution to Moyjil over the next year or two, because I think we'll pull in some researchers with different ideas, as long as the Traditional Owners are happy for us to keep investigating," he said.
"You can't underline enough that they will have a significant say about what happens from here on."
What Dr Sherwood can assert with confidence is that Aboriginals had been settled at the Moyjil headland for at least 30,000 years.
And while the landscape would have been nearly unrecognisable, with lower sea levels, the cliffs and headland itself have most likely been relatively unchanged.
"In all probability there was mega fauna in the landscape - giant Diprotodons and Tasmanian tigers running all over the continent along with marsupial lions and giant wombats," he said.
"And the climate was probably different, so the lifestyle of Aboriginal people would be very different.
"But when you look at the shellfish in that 120,000-year-old midden site, they're the same as the ones on the beach today ... the main food items looking after people on the coast now were there then - the last time sea level was as high as now."
One of Dr Sherwood's favourite expressions is "chance favours the prepared mind".
"If you're thinking about it and you're looking for it, you might just spot something," Dr Sherwood said.
And it's not hard to see why.
The Deakin University Associate Professor in environmental science was first introduced to the Moyjil site by geologist Edmund Gill, who was in turn contacted by local naturalist Jim Henry in 1981.
Henry's daughter, Catherine MacDonald, told The Standard her father would be "overjoyed" at the research produced by Professor Sherwood and Moyjil team.
"It's gone gangbusters," she said.
"He was a very humble person and he would have felt very proud that the research he did and what Professor John Sherwood has been doing has furthered what we know about Aboriginal settlement within Australia.
"Dad was instrumental in the search for the Mahogany ship and he was hoping at some stage in his life they'd find it, but not realising that what he found at Moyjil was probably more significant and had potentially far-reaching consequences for humanity."
And for Peek Whurrong elder Rob Lowe, who has been personally involved with the project since 2013, the papers released in March were a welcome vindication of long-held knowledge.
"It just goes to show we're not Johnny-come-latelys, we've been around for a long time," he said. "So that's the most pleasing thing about it."
However Mr Lowe, who has known Dr Sherwood since they both played Warrnambool and District league football in the 1980s - he played for Merrivale while the scientist played for the now-defunct Deakin University Sharks - said he had concerns for the broader preservation of history in the region.
Mr Lowe said in terms of the Traditional Owners, Levy's Point beach held just as much significance as Moyjil and warned against the prospect of increased horse training in the area.
"They're both Indigenous places," he said. "It's just that one is protected and the other could be destroyed.
"If there's a permit given for horses to run through those dunes, then our history is gone.
"So we can't make a big deal about Moyjil without looking at other sites in the area - they're all important."
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