x32 ARTEFACTS COLLECTED 
with stone knives, and prise off the slabs with a long, slightly 
curved and flat bone tool, resembling a thick paper-knife in 
shape. One of these was found on the Cape Horn Islands 
and was given to Spencer. It is shown (J size) in Fig. 8, 
no. 6, and is almost 25 in. long and i| in. wide; the surfaces 
are flat and the edges rounded. The Yaghans call this imple¬ 
ment suf-sta , and use it for pushing up behind the bark from 
below. The suf-sta is sometimes a foot longer than the 
present one. 
Many wedges of whale-bone were found in middens on 
Navarin Island (Fig. 10, no. 1). These are roughly made, 
more or less parallel-sided, cut and ground at one end to 
a curved cutting-edge. The other end is squared and most 
of the examples show signs of crushing by heavy blows at 
this end, caused, no doubt, when the wedges were driven in 
for splitting wood, possibly for building plank-canoes. The 
bone used appears to be cetacean ribs, a very suitable material 
for making wedges, since the denser, indurated outer bony 
layer resists wear, while the softer cancellous interior tissue 
would be worn away far more rapidly, thus causing the edge 
to remain sharp during use, in the same way as a rodent’s 
incisors are automatically stropped in use by the more rapid 
wearing away of the dentine at the back, as compared with 
the thin front layer of enamel which is far more durable and 
wear-resisting. The wedge figured (Fig. 10, no. 1) exhibits 
a quantity of hacked scars upon the upper portion of the flat 
outer surface of the bone. These scars may have been caused 
by using the bone as a chopping-block. They remind one 
very much of the very similar scarring on the surface of 
many of the bones found by Monsieur Henri Martin at La 
Quina, associated with remains of Moustierian culture. But, 
more probably, they were deliberately produced, to roughen 
the surface and give a better grip to the fingers while holding 
the wedge during the hammering. The opposite (inner) 
