Geology of Rainforest Aboriginal Stone Tools

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Traditional Aboriginal Knowledge

Geology of Rainforest Aboriginal Stone Tools

'this page currently under development..."

Ooyurka - T-shaped Tool
Morah Stone
Waisted Axe
Ground Edge Plain Axe
Worked Edge (chipped) Axe
Broad Axe
Geology of Stone Tools - under development
Structure and Function - under development

Ooyurka - unique T-shaped stone tool of the Wet Tropics Aboriginals

What is an Ooyurka?
It is an Ooyurka if it is found in the far north Queensland region. It is a stone tool unique to the rainforest region.  An Ooyurka needs to have some kind of shoulder waisting, the orientation of the face has to be perpendicular, and there needs to be some residue of polish, or organic material in the working face. There is a narrowness of the working face and it should be a slate (there are some schists, and 2 basalt ones found but the rest are argillaceous or spotted hornsfels slate). The working face may be convex, concave or flat.


What were Ooyurkas used for?
 80-90% of Ooyurkas have been discovered.  them have been dug up by ploughs while planting Sugar Cane. None have been carbon dated.
It is suggested that they are no older then 5,000 year old(but there is no solid evidence to support this claim), yet no one from the Dyirbal or Yidin clans know how to use the Ooyurka nor know what they are for.
Also, Ooyurka is not a word from the language of these two rainforest clans.  
Kennedy in 1949 suggested the stones were used to smooth the modern Aboriginal tools. It appears the Rainforest Aboriginal made wooden swords.

  During the wet season, the people of the rainforest were quite sedentary and would spend their time based in the one location. They built substantial large huts up to 9m long and 3m high that connected to other large huts via internal doorways.

The case against them being used as "nutcrackers"
When the green cicada called they knew the bush turkey would be laying it's eggs and the mountain rainforest "nut" trees would be bearing fruit. They went to areas in the rainforest where there were nut trees, often farmed by removing unwanted saplings), harvest the nuts and storing them in the ground under "climate controlled" conditions (damp pits) until they were ready for use.
There were four kinds of nuts generally harvested (listed least toxic to most toxic) Black Walnut(Endiandra palmerstonii) --> Hairy Walnut ( Endiandra insignis ) --> Black Bean (Castanospermum australe) --> Beilschmieda bancroftii (yellow walnut)
The black walnut (due to it's appeal to local animals) needed to be harvested by climbing up in the rainforest canopy using lawyer vine
Other sources include: Kuranda quandong (Elaeocarpus bancroftii), Black Pine(Sundacarpus amarus), Macadamia whelani (macadamia nut).
It is said that the ooyurka was left behind in their shelters and used by others or used by themselves when they returned back to the area at commencement of the next wet so the tools was used primarily during the "wet season"
They became more mobile and got into  hunting once the drier season started. This could entail a journey from the mountains to the coast where they built substantial , complex fish traps along the river flatlands. These fish traps needed to be re-constructed on an annual basis to to seasonal flooding.
Nuts are very hard and the working edge of the ooyurka was often less than 15mm wide and this is less than these nuts, so often the working edge would bounce/slide off the nut and hit the anvil surface, often causing damage to the (pretty soft) edge of the Ooyurka. These kind of slates have a Mohs scale rating of 3 at the hardest! None of the original ooyurkas showed this kind of damage.
Besides the rainforest people had excellent two piece nutcrackers. - a flat rock with incised pits, just the size of the nuts and a hefty hammer stone.

Geology and surface features
Ooyurkas are made from
(The choice of these rock types is significant and will be covered in detail as this web site develops)

Speculative Conclusions

 Wet season use.
Ooyurka could  also be used to pare bark away from stems or tree trunks to make rope, twine, thread for bark blankets from the inner bark of the Red Tulip Oak(Argyrodendron sp.)
 and could have been used in wooden tool making from spear shafts to, boomerangs to shields. Most likely nothing to do with food at all.

(April 2017 webmaster pers comm.with traditional owner)
(All ooyurka held  by the webmaster clearly fit best in the right hand only)
Female use Ooyurka 
Male use Ooyurka:

Morah Stone

morah stone

(The following is an abridged version of a paper about starchy residues on Morah stones)
Grindstones from Australia are known to be used for a variety of functions including plant processing, preparation of ochre and also for the maceration of foods such as lizards and cats (Gould 1980; Mitchell 1848).
Grindstones are common in the tropical rainforests of far North Queensland and have often been found by farmers ploughing paddocks (Woolston & Colliver 1973).
One particular type of grindstone, referred to as the morah stone, comes from a well defined area from Tully in the south, to Cairns in the north and west to the Ravenshoe area on the Atherton Tablelands (Woolston and Colliver 1973:117).
Morah stones (sometimes referred to as graters by locals) are made from grey slate, a soft and brittle stone that is available locally.
They are distinguished from other grindstones by a series of incised grooves running perpendicular to the axis of the artefact.
Maisie Barlow, a Jirrbal elder from Ravenshoe, relates that the incised grooves were made with quartz pieces, though bone points have also been suggested as tools for this purpose.

(Webmasters personal opinion is that the morah stones were the ideal surface with which to remove and collect the thin flesh of the ubiquitous and long fruiting varieties of widely available quandong.
In addition there are other fruits in the rainforest with large seeds surrounded by a thin but edible layer of flesh that would be suitable.
You simple roll the ripe quandong across the surface with the palm of your hand and the skin and flesh come off onto the surface and into the grooves.
The flat morah could also be used as a "plate" to keep crushed nuts out of the dirt  - hence the starchy residue.
As with the Ooyurka there is no reason other than "Western thinking" to think that a stone tool requiring great labour to produce would be limited to a single purpose.) 

Morah stones occur in a region where the processing of toxic starchy plants is common (see Pedley 1993), and their use may be tied to the extended processing of these economically important foods.
Morah stones are described by an unidentified Nutjen (Ngatjin) woman to be used in a ‘rolling crushing’ motion rather than grinding (Woolston & Colliver 1973). These were said to be used to crush zamia and walnuts.

The upper stones are known as ‘moogi’, the name given by the same informant describing the use of morahs referred to by Woolston and Colliver (1973:118) and are documented in the Australian and Queensland Museum collections.
Moogi are usually a granite raw material, which are much harder than the slate of the morah stones. Horsfall (1987:209-211) measured over 58 morahs (22 whole and 36 fragments) and found that none of them were more than 65 mm thick, though in this study the thickness of the grindstones did not exceed 30 mm.
The thickness of the grinding stones is argued to be a function of the local slate raw material, which tends to cleave into relatively thin plates. Some of the morahs examined by Horsfall had incised grooves on both surfaces but most had incisions on only one surface. Used surfaces tend to be flat to concave, consistent with documented grindstone wear patterns (see Field & Fullagar 1998; Smith 1985).

Very few complete morahs are known and the largest morah we have observed was nearly 50 cm in length, and while broken, was mostly complete and in a private collection near Innisfail. Morahs are known from the Atherton  Tablelands.

Combined with overall morphology and related use-wear studies, the function of morah stones will be discussed. Unused surfaces were smooth and featureless and not incised.
Ethnographic observations of the processing of starchy foods indicate that all surfaces of the grindstone will generally become covered in starchy material and any flaws, or incised surfaces are likely to act as residue traps.
Combined with residue studies and morphological analyses, use-wear analysis is an informative adjunct for identifying patterns of wear and probable tasks (Fullagar et al. 1996).

Of the eleven morahs that were sampled for this analysis, one grindstone yielded no starch at all, while the remainder produced variable amounts of starch.  Some starch grains are very distinctive and require very few grains in order to estimate the likely species of origin - for example tubers and some grasses - however for the species likely to be represented here such as Cycas media and Beilschmieda bancroftii (yellow walnut) the overlap in size and similarities in morphology demand a larger sample for examination.

except perhaps for far North Queensland rainforests where the morah or incised grinding stone is a common feature of the archaeological record (Cosgrove 1996; Cosgrove et al. 2007).

Combined with the morphology and associated use-wear patterns described below, there is compelling evidence to suggest that morah stones were used as grinding stones. On similar artefacts examined by Richard Fullagar, fine striations were found to occur at right angles to the incisions on the surface; they exhibit abrasive smoothing from grinding; and develop limited polish (polishes appear to develop on hard quartz grains within the stone matrix) - this is consistent with plant working.

 It has also been noted that undertaking use-wear studies on this type of stone is problematic as the raw material is very soft and residue films obscure the surface. Nonetheless, taken together, the morphology, residues and information about use-wear on similar implements are consistent with plant processing, in this case toxic starchy plants, most probably dominated by the Yellow Walnut ( B. bancroftii ) and also Hairy Walnut ( E. insignis ).

Establishing the use of morahs for the processing of toxic starchy plants has implications for our understanding of the timing and nature of permanent settlement of rainforest environments. Long term use of rainforest environments by people may hinge on access to a suite of toxic starchy plants (see Cosgrove et al. 2007). The development of the technologies for processing plants such as the Black Walnut(Endiandra palmerstonii) , Yellow Walnut and Black Pine(Sundacarpus amarus) may have been transferred from the known methods for processing cycads, the antiquity of which has been reported as 13,000 years in Western Australia (Smith 1982, 1996).
Method of toxic food processing:
Cycas media is a common feature of the vegetation in the dry country on the margins of the rainforest, and the methods for processing these and the rainforest species are essentially the same – baking the starchy kernels for c. 6 hours followed by pounding to a paste, then leaching in running water for several days. The second step in this process, pounding to a paste, can also be achieved by grating with a shell (Pedley 1993).

In these studies, three separate lines of evidence are used to determine function (see Fullagar et al. 1996).
  1. Firstly, a technological study indicating that the morphology of morahs is typical of grinding stones – they are flat, with one or both surfaces showing evidence of use. The used surface is identified by the presence of concave areas where the surface has been worn down by continuous grinding. Peculiar to morahs are the incised parallel lines that run perpendicular to the maximum length of the stones.
  2. Use-wear studies, the second stage in the functional analysis, indicate that these may have been made by quartz flakes as evidenced, by the sharp angular cuts and cross sectional characteristics. The raw material, slate, is a very soft stone and as such the incisions would have been relatively easy to produce. The incisions in the slate grindstones may serve the same purpose as the pecked surfaces observed on sandstone grindstones. In the latter case it is a method used to rejuvenate the grindstone surface to facilitate the breaking up of grass seed husks. The incised surfaces are always the used surfaces on the morahs.
  3. The residue study which was the focus of this research has shown that the incised surfaces provided ideal locations for preservation/recovery of starch. Most of the artefacts sampled produced starch grains, though in greatly varying quantities. The variations may relate to the storage conditions of the morahs which were different in each case. Nonetheless the starch recovered has provided a clear indication of target species on the basis of maximum dimension measurements (see Lance et al. in press). While these stones appear to have been used for the processing of Yellow Walnuts and Hairy Walnuts, it is also clear that they were used to process other toxic nuts, perhaps as they became seasonally available. It is likely that these residues represent a record of the last use of the stones.
An interesting find is that the one stone, was used to process a different set of plants to the other grindstones examined here, as indicated by the small sample of starch granules present on the stone surface. One of the species that may be present on this grindstone is Macadamia whelani (macadamia nut). Pedley (1993:139) reports that no information was found in relation to the processing of M. whelani by Jirrbal-Girramay informants, nor from Murray Upper, near Tully, and it may not have been processed uniformly across the region where the morah stones are found. The identification of this plant as part of the assemblage on this grindstone may be an indicator of detoxification closer to Babinda.

A second species possibly identified on this stone, the Polynesian Arrowroot ( Tacca leontopetaloides ) is found on the coast in ‘open forests and extends into rainforest behind sandy beaches’ (Pedley 1993:117) and as such may act as an indicator of the location from which the stones are derived (i.e. coast as opposed to tablelands).
Morah stones are used in the processing of toxic starchy nuts. Comparison with modern reference materials indicates that these plants are likely to include:
We would like to thank Maisie Barlow (Jirrbal), Pat and Alverio Croatto, Ned Maxwell, Deanna and Ron Stager for access to their private collections of morah stones. The Atherton Tropical Herbarium staff, especially Rebel Elick and Bruce Gray, helped us compile the plant/starch reference collections. Thanks to Don Page, Bernadette McCall and Anna Charlton for technical assistance. We are also grateful to Ernie Raymont (Ngatjin) for advice and support. The project was funded by an Australian Research Council Discovery Project grant, La Trobe University and the University of Sydney. We appreciated the constructive comments of Alison Crowther and Catherine Westcott. The authors acknowledge the facilities as well as scientific and technical assistance from the staff in the Australian Microscopy and Microanalysis Research Facility (AMMRF) and at the Australian Key Centre for Microscopy and Microanalysis at the University of Sydney. Barton, H. 2007. Starch residues on museum artefacts: implications for determining tool use. Journal of Archaeological Science 34:1752-1762.

Waisted Axe

waisted axe

Ground Edge Plain Axe

plain axe

Worked Edge(chipped)Axe

worked edge axe

Broad Axe

(add image large broad axe with reasoning for it's use in nut crushing and preparation)

broad axe suggested use crushing nuts