Records of the Western Australian Museum 17: 461A162 (1996). 
Short communication 
An unusual button-form australite from Earaheedy Station, 
Western Australia 
W.H. Cleverly 
Western Australian School of Mines, P.O Box 597, Kalgoorlie, Western Australia 6430 
Australites collected from No.l Marracoonda 
Paddock, which is centred 25°52'S, 121°53'E on 
Earaheedy Station, include an unusual form of 
button (Figure 1A—D). Flange has developed 
outward and unevenly instead of coiling backward 
from the direction of flight into a regular toroidal 
form. The dimensions of the button are 14.0-16.0 
mm diameter x 7.1 mm thick and the weight is 1.51 
grams. 
The outwardly directed flange (Figure IB) 
characterizes buttons of the unusual type studied 
by Chapman (1964), who reproduced similar 
shapes from glycerine glass in wind tunnel 
experiments and enunciated the aerodynamics. 
Unlike the two buttons studied by Chapman, the 
Earaheedy button has no obvious flow ridges upon 
the anterior surface of flight (Figure ID). However, 
the edge of the anterior surface has superimposed 
scallops (Figure 1C), and the low, eyebrow-like 
ridges bordering the scallops probably constituted 
a single, almost circumferential flow ridge of 
peculiarly scalloped shape. 
The Earaheedy australite experienced a smaller 
ratio of body force to aerodynamic force (Chapman 
1964) than the other known examples of its type, 
and has therefore a less exaggerated extension of 
the flange. 
The type buttons and the one from Earaheedy 
Station are the only three on record but the form 
might not be as rare as would appear. Additional 
specimens could have been misidentified and 
dismissed as "button cores" i.e., buttons of the 
common type from which weakly attached flange 
had broken away. The deceptive similarity of the 
posterior surfaces of flight is illustrated by the 
Earaheedy button (Figure 1A) and a "button core" 
in the same collection from No.l Marracoonda 
Paddock (Figure IE). The anterior surface of the 
button (Figure ID) shows that the irregular outline 
is a consequence of the different extents of the melt 
streams and not a consequence of fracture. 
One of the type buttons was found within an 
area spanning the eastern half of the South 
Australia/Northern Territory border; the other 
was found near Gladstone, Tasmania. Those find 
sites and No.l Marracoonda Paddock are within 
the two sectors of occurrence of very heavy 
australites (Cleverly and Scrymgour 1978), but as 
there are only three known specimens, this 
distribution might be fortuitous. 
Figure 1 Two australites from Earaheedy Station. 
Scales are a centimetre divided into 
millimetres. A-D: Unusual button form. A: 
Posterior surface of flight showing 
deceptively broken-looking outline. B: Side 
view with direction of flight towards bottom 
of page showing stubby, outwardly directed 
flange. C: Oblique view of anterior surface 
showing three of the peripheral scallops with 
marginal flow ridge. D: Anterior surface of 
flight showing tendency to petaled shape. E: 
"Button core", posterior surface with broken 
outline resulting from loss of flange. 
