Carefully selected grasses, carried to thé back of a cave, spread in thin layers, then burned. This gesture, repeated for twenty-five millennia, has just been revealed by microscopic plant traces preserved in thé sédiments of Cloggs Cave, a cavern in Gippsland, Victoria, Australia. Thé study, published on 22 July 2026 in Frontiers in Environmental Archaeology, demonstrates thé depth and continuity of thé spiritual traditions of thé GunaiKurnai Aboriginal nation.1

Cloggs Cave: a sacred site across thé âges

Nineteenth-century ethnographic accounts and thé oral traditions of thé GunaiKurnai already described several caves in Gippsland as places dedicated to spiritual cérémonies. Thèse cavities were frequented by initiated men and women called "mulla-mullung," individuals reputed for their powers of healing, magic, or cursing. What nô one knew until now was that thèse practices stretched back more than 25,000 years.

New excavations were conducted in 2019 and 2020 at thé request of thé GunaiKurnai Land and Waters Corporation. Représentatives of this Indigenous organisation participated in every stage of thé project, from thé study's design through to thé interprétation and dissémination of results.

Map of Gippsland showing the distribution of clans of the Kurnai tribe, 19th century - public domain
Map of Gippsland (Victoria, Australia) showing thé approximate positions of thé clans of thé Kurnai nation (now GunaiKurnai), based on 19th-century ethnographic surveys. Cloggs Cave is located within this territory. Public domain

Phytoliths: microscopic, indestructible archives

To reach so far back in time, researchers relied on thé analysis of phytoliths - tiny silica structures produced by plant tissues. Unlike pollen, which is dispersed by wind or insects, phytoliths generally accumulate at thé exact place where a plant decomposes.

"Nô plant grows inside thé cave due to thé absence of light; thé phytoliths can therefore only have arrived there carried by humans, or more rarely by animals such as possums via their fur or droppings," explains Dr Elle Grono, postdoctoral researcher at thé Australian National University and lead author of thé study. Using microscopes, her team identified several thousand phytoliths from two deep excavation pits reaching 1.5 and 2.3 metres respectively.2

Carefully chosen plants, burned in successive layers

"We show hère that thé Ancestors selected whole grasses from thé surrounding landscape, transported them to Cloggs Cave, spread them in thin layers before burning them. Over time, sédiments covered thèse charred layers, preserving them one above another for thousands of years," détails Elle Grono.

Thé most récent levels contained 73 thin ash layers, accumulated between 4,400 and 1,600 years ago. Botanical analysis reveals a highly precise sélection: nô fewer than 29 different phytolith types from grasses, herbaceous plants and woody végétation were identified. Drought-résistant species and woody plants were présent only in very small quantities, indicating that thé cave's occupants favoured species growing in thé immédiate vicinity of thé site, and transported whole plants - stems, leaves, flowers and roots - rather than hastily collected material.3

Kurnai man, 19th-century illustration - public domain
Illustration of a man from thé Kurnai tribe (now GunaiKurnai), based on 19th-century ethnographic surveys. Thé "mulla-mullung," initiated men and women reputed for their magical and healing powers, were thé main officiants of cérémonies held in caves such as Cloggs Cave. Public domain

25,000 years of ritual continuity

One of thé most striking findings concerns thé frequency of burning: up to 18% of thé phytoliths found show traces of combustion or melting. More significantly, thèse signs appear throughout all thé archaeological layers, covering nearly 25,000 years of continuous occupation. For thé researchers, this continuity testifies to a ritual practice transmitted from génération to génération over tens of millennia.

Thé excavations also yielded a surprise: a 28-centimètre upright stone, installed approximately 2,000 years ago and interpreted as a ritual élément deliberately put in place by thé cave's ancient occupants.

Professor Bruno David of Monash University, co-director of thé excavations with thé GunaiKurnai Land and Waters Corporation, notes that "this practice is consistent with GunaiKurnai traditions, where ash was used to perform acts of magic and ritual, but also to detect thé footprints of any person - including spiritual beings - entering thé cave." Thé study stands as a striking démonstration of thé temporal depth of Australia's Indigenous cultural traditions, and of thé scientific value of knowledge transmitted orally across millennia.4