A drone carrying a laser scanner has located three previously unregistered rock shelters in the Blue Mountains of New South Wales, all holding stone artefacts and one of them marked with a pair of red hand stencils. The survey, led by digital archaeologist Dr Jacob Bongers of the University of Sydney, also confirmed six shelters already on the state register and placed them more accurately than the register did.
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The work was done in partnership with the Dharug Custodian Aboriginal Corporation, and the three finds sit on Dharug Country. Only an estimated 10 percent of the region has been surveyed, according to co-director Dr Amy Mosig Way, which means the three new records say as much about how little of the sandstone country has been walked as they do about the shelters themselves.
The three shelters the paper names, one by one
The University of Sydney release, distributed through EurekAlert on 19 October 2026, describes the three as rock shelters with rock art and stone artefacts and does not separate them. The peer-reviewed paper does. In Remote Sensing, the team lists them as BM139, BM140 and BM141 and gives each a name: Djulpura 1, Djulpura 2 and Djulpura 3, with register numbers 45-4-1831, 45-4-1830 and 45-4-1829 respectively. Those numbers come from the state’s Aboriginal Heritage Information Management System, the register the release says the drone coordinates improved on. All three lie in the sandstone country between Bells Line of Road and the Grose Valley, within two survey blocks the paper labels DJ1 and DJ2.
BM139, Djulpura 1 Shelter with Artefacts, lies in survey area DJ1, south of Bells Line of Road, north of the Grose Valley and just east of Bell. The paper records three large stone artefacts on the shelter floor. It is the plainest of the three, a site whose evidence is entirely on the ground surface and which a walker could pass without seeing.
BM140, Djulpura 2 Shelter with Art and Artefacts, is also in DJ1 and is the one that carries the hand stencils. The team counted 21 stone artefacts on the floor and one art panel. On the panel, two red-pigment hand stencils sit side by side, about 35 by 15 centimeters in total, a left hand directly beside a right hand. The authors judge that they were most likely made in a single event by the same individual. The panel is slightly angled and lies beneath a band of iron-rich stone, with some exfoliation at the top of the stencils.
BM141, Djulpura 3 Shelter with Artefacts, is in the second survey area, DJ2, near the Pierces Pass walking track. A brief surface inspection turned up 26 stone artefacts. The paper does not mention rock art at this shelter, which differs from the release’s general wording that all three hold art, so the fullest account is that stencils are documented at Djulpura 2 and artefacts at all three. The shelter is cut into cross-bedded quartzose sandstone with thin lenses of pale, fine-grained material that the team provisionally reads as a claystone lens within the Banks Wall Sandstone.
DJI M350 and YellowScan Explorer V2: how a drone sees through the bush
The platform was a DJI M350 drone carrying a YellowScan Explorer V2 sensor. Lidar fires laser pulses and times their return; because some pulses slip through gaps in the canopy and reach the ground, the resulting point cloud can be stripped of vegetation to show the terrain beneath. Sandstone shelters form under cliff lines and overhangs, which show up as distinctive shapes in such a model even where the forest hides them from the air.
According to the paper, the team flew at 75 meters above ground level at 7 to 10 meters per second in crosshatch patterns, collecting at least 100 points per square meter. Positions were post-processed against a Leica GS16 base station to better than 10 centimeters, horizontally and vertically. The survey also drew on public New South Wales airborne lidar, which is coarser at a minimum of 0.5 points per square meter. Candidate overhangs were then ground-truthed on foot, with a Leica laser distance meter used for shelter dimensions and a GNSS receiver recording each shelter’s drip line to centimeter accuracy.
Custodians, funding and a region still mostly unsurveyed
The Dharug Custodian Aboriginal Corporation, based in Windsor, is the custodian partner, and one of the paper’s authors, Erin Wilkins, is employed by it. At the corporation’s request, site coordinates are withheld from the paper. The other authors are Bongers, Wayne Brennan, Lauren Roach, Emily Nutman, Joseph W. Lehner and Amy Mosig Way, drawn from the University of Sydney and the Australian Museum. The Dharug are the Aboriginal people of the Sydney basin and its western ranges.
Brennan, the project’s co-director and a rock art specialist, said the work shows the importance of listening, learning and working together. Bongers said the approach is exciting because it offers an efficient and accurate way to locate sites in rugged environments. Mosig Way, also a project co-director, pointed to the value of giving students practical experience in cultural-heritage research. The release credits A$248,610 from Round 1 of the Australian Government’s First Nations Heritage Grants program, and says the project also created hands-on cultural-heritage research opportunities for students.
More than 200 rock shelters with cultural evidence are already recorded across the Blue Mountains, a figure that Mosig Way’s estimate puts against a region of which about a tenth has been surveyed. The survey’s accuracy claim is specific: the drone work produced better coordinates than the state’s heritage register for the six shelters it re-located. The paper itself is open at its DOI.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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