THE TASMANIAN NATURALIST. 
which, for want of a 'better term, we 
may designate the upper side, shows o 
flatly concave rather rough depression of 
4Jin. by 4in. diameter. If a ruler is 
placed on the top, its deepest part is 
about Jin. below the ruler's edge, but as 
it is fair to assume that the original sur¬ 
face was not absolutely Hat, it is pro¬ 
bable that a lenticular part of the pebble, 
measuring 4jin. by 4iu., and nnving a 
greatest thickness of Jin., has been ’re¬ 
moved. Tlie surface is rough; but it is 
also unquestionable that the original 
roughness has been smoothed down 
by rubbing or grinding. The op¬ 
posite lower side is slightly con¬ 
vex, and in it s centre there is an 
irregularly shaped, very rough mark 
of -about 2]in. diameter. This murk clear¬ 
ly shows that it lias 'been produced by 
numerous blows applied to this part of 
the surface. The peripheral edge is 
rounded and smooth. Specimen > F2, 2A, 
2B, which I found near Kenipton, is an¬ 
other type of jin's kind, though some¬ 
what differing from the former. It had 
been broken into six pieces, and 1 suc¬ 
ceeded in getting all of them but one, 
though they had been scattered over an 
area of about 100 square yards. When 
pasted together they proved to be the 
finest specimen that has so far come tin¬ 
der my notice. It is almost completely 
circular, measuring 6Jin. in diameter, but 
only 2Jin. in thickness; it is, therefore, 
strongly compressed. The weight is 51b. 
8oz. avdp. Tiie rock is a coarselv- 
grainod quartzitic sandstone of slightly 
pinkish colour, though in some pans this 
has been replaced by a whitish colour. 
The upper side is almost to Its whole ex¬ 
tent hollowed out, and therefore con¬ 
cave. As in its deepest part it iias been 
hollowed out to a depth of Jin., and as 
it is only fair to suppose that the origi¬ 
nal surface was the same as the convex 
lower side, we assume that a lenticular 
mass of stone of Jin. thickness, measur¬ 
ing about 5Jin. in diameter, lias been 
tediously removed by grinding. The 
peripheral edge is well rounded, but it 
seems that it has been considerably be¬ 
laboured by heavy blows, whose traces 
are very conspicuous. The most common 
type is represented by Fig. 3. This spe¬ 
cimen comes from the South Arm, and 
measures 5in. in length, 3Jin. in width, 
and ljin. in thickness, weighing 21b. loz. 
avdp. It is regularly oval in shape, 
though the two longitudinal sides are 
slightly flattened; it is rather compressed, 
but the upper and lower sides are slightly 
convex. The material is dark, rather fine¬ 
ly crystalline Diabas. The upper side 
shows in the centre a deep rough depres¬ 
sion of about Jin. diameter, and around 
it the surface is nicely polished and 
smooth. Exactly opposite on the lower 
surface is another rough mark, though 
not quite us well defined. The peripheral 
edge is rounded, but the two longitudinal 
riii's snow distinctly that it lias 'been 
flattened off, and marks of blows are 
also visible at either end, on the shorter 
sides. A similar specimen is figured in 
Fig. 4. This has been found at Sliene 
(Portville), and it measures Tin. by 4]in., 
the thickness being barely ljin. The 
weight is 21b. 13oz. avdp. the shape 
is irregularly oval, and it is unquestion¬ 
ably t!u»t of a flat pebble that had been 
picked up in tile nearest creek. The ma¬ 
terial is Claims, the black crystals of 
aiigite, contrasting sharply against the 
greyish green ground mass. The upper 
.side inis apparently been smoothed, and 
in tlie centre is a deep, rough depression, 
measuring about lin. in din meter. No 
such depression exists on tlie opposite or 
lower side, which represents the unaltered 
original surface of the pebble. The differ¬ 
ence in the smoothness of the upper and 
loner side Is very markeJ; the loner s'ide 
shows that smoothness so peculiar to 
water-worn pebbles, but oil the upper 
side it has disappeared, and been replaced 
by a surface showing numerous fine 
streaks or scratches, ail running in the 
same direction, such as are produced by 
a rubbing or grinding action. Tile most 
piculiar and perhaps the most interest¬ 
ing type is reproduced iu Fig. 5. This 
lias been found on the famous camp 
at the Did lleach by Mr. Anthony. It is 
an oval pebble of Diabas, measuring oin. 
in length, 3Jiu. hi width, but only 1 Jin. 
in thickness, and weighing lib. Soz. avdp. 
Both the upper and lower -ides are 
tint, but while the lower side is rather 
rough, probably owing to weathering, tlie 
upper siifc has been most elaborately 
polished and ground. The grinding lias 
even been extended to the peripheral 
part, and a fine edge lias been produced 
When held in favourable iiglit. three 
rough marks can be seen cross¬ 
ing obliquely; it is probable that 
these are parts of the original surface, 
which have been preserved during the 
grinding. Tile specimen is well preserved, 
except for a large fragment broken off 
from the margin. The above are only a 
few of the specimens 1 have examined, 
but they serve as good illustrations of 
the type’s met with, and we ore now -able 
to draw a few general eone'usions. 
Everyone of the specimens that has come 
under examination proves by its general 
shape that it was originally an ordinary 
water-vvortf pebble, such ns may be pick¬ 
ed up in nny stream or alluvial boulder- 
bed. It was certainly essentia' tiiat such 
a pebble should be fiat—that is to say, 
that width ami breadth exceeded the 
thickness, inasmuch ns pebbles of this 
tvpe are always naturally of on elliptical 
or round shape. It appears that the 
general outline was more of a secondary 
