Webb: Grinding patches on granite bedrock around Cue, WA 
Table 1 
Dimensions in millimetres of all the measurable grinding patches noted at granite exposures around Cue (Gunn & Webb 2006). The 
patch numbers match those in Figures 2-6. 
patch 
Afghan Rock 
Boat Hole 
Camel Soak 
Djungari 
Pool Pddek 
Taincrow 
1 
260 X 170 
300 X 160 
750 X 600 
230 X 130 
400 X 200 
200 X120 
2 
360 X 260 
250 X 160 
250 X 150 
280 X 220 
150 X 100 
3 
520 X 280 
380 X 150 
400 X 200 
270 X 230 
4 
II 
650 X 450 
270 X 170 
200 X 180 
210 X 150 
5 
500 X 320 
500 X 250 
310 X 290 
350 X 250 
6 
broken 
550 X 300 
200 X 120 
7 
broken 
400 X 220 
250 X 140 
8 
broken 
350 X 200 
9 
350 X 350 
300 X 250 
10 
330 X 200 
170 X 120 
11 
340 X 220 
160 X 120 
12 
400 X 250 
350 X 220 
13 
660 X 350 
350 X 180 
14 
380 X 300 
280 X 180 
km radius of Cue. No grinding patches were found at the 
other granite exposures situated near water that we re¬ 
inspected. 
Analysis 
The position of each grinding patch was determined 
by placing a Global Positioning System receiver (GPS 
receiver) in the middle. Each patch was measured along 
its longest axis (length) and orthogonally (width) (Table 
1). Depth was not measured, it was too slight: < 1 mm. 
Three patches could not be measured because the 
bedrock on which they had formed had subsequently 
broken, leaving one or other axis incomplete. Individual 
patches range in size from 150 mm x 100 mm to 750 mm 
X 600 mm (Table 1). Mean size is about 300 mm x 200 
mm; approximating the average size, 310 mm x 160 mm, 
reported by Grant (1992) for the 487 grinding patches she 
measured on granite bedrock at Esmeralda Station in 
northwestern Queensland. 
It is probable that patch size relates to the ergonomics 
of grinding, on which there are no data; so 1 
experimented. A muller can comfortably be pushed about 
450 mm away from oneself, when seated cross-legged. 
Grinding the area immediately in front of one's crossed 
legs is difficult, however. Hence, the area ground 
stretches about 300 mm away from the person doing the 
grinding; the orthogonal dimension may be more 
variable. 1 could comfortably cover an area about 400 mm 
wide. Several of the patches reported on here are much 
larger than 300 mm x 400 mm, however. All the very 
large patches are at Boat Hole Rock and Camel Soak. 
They could be the result of two separate patches merging 
over time, or be places where two people worked 
together, although the worn faces are evenly smooth, or 
they may simply be different from the smaller patches. It 
is impossible, as yet, to discriminate between these 
suggestions. 
The grinding patches at Boat Hole Rock and Camel 
Soak might also be bigger than those at Afghan Rock, 
Djungari and Taincrow because water was available 
more frequently or more reliably at Boat Hole and Camel 
Soak, allowing greater numbers of people to camp there 
more often or for longer periods than at the other sites. 
Boat Hole gnamma is capacious and easy to cover, being 
long and narrow. It would have been an important 
source of water to people living in the area in the 
archaeological past because no other water sources are 
known within a radius of several kilometres. On the 
other hand, few artefacts were noted on the colluvium 
west of the outcrop in which this gnamma has 
developed; occupation seems to have taken place 200 m 
to the east at a short stretch of breakaway, where there is 
a sparse artefact scatter (Gunn & Webb 2006). In contrast, 
an extensive artefact scatter was found at Camel Soak, 
the site was visited often and/or for long 
periods and/or by many people. More sites where 
grinding patches on bedrock are situated close to water 
would need to be found around Cue before the 
significance of the pattern just described could be 
assessed, however. 
The grinding areas on 17 grindstones were measured 
during earlier surveys around Cue (Table 2). In Figure 7 
their dimensions are compared with those of the 
grinding patches on bedrock. This Figure shows that 
there is no appreciable difference in size between the 
ground areas on flat and dished grindstones, but that the 
grinding areas on grindstones are usually smaller than 
those of bedrock patches. 
The grinding area on a grindstone is, obviously, 
always smaller than the host rock, who.se dimensions 
were probably constrained by weight. Grindstones must 
be portable. They are usually made of stone not available 
in the immediate vicinity of where they are found. All 
the grindstones listed in Table 2 were made from granite. 
The weight of the largest is estimated to be 29 kg, based 
on the average density of granite; 2.8. This is about the 
maximum weight one person can lift and carry easily. 
The large granite slab hosting grinding patch 1 at 
Taincrow Rdckhole is estimated to weigh about 375 kg 
and is probably in situ. Weight restrictions obviously do 
not apply to bedrock, hence grinding areas can be bigger, 
as the very large patches at Boat Hole and Camel Soak 
demonstrate. Until more grinding patches on bedrock are 
found in this region, the difference in size between them 
and the grinding areas on grindstones cannot be 
explored further. 
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