928 NOTES ON SOME ROCKS AND MINERALS FROM NEW GUINEA, &c. 
to contain minute traces of gold, but only by operating upon large 
quantities. 
Some of the pebbles of quartzite were black, others only black 
in the interior ; the former had probably not been burnt in the 
aig fireplaces. 
nt.—In the form of light brown pebbles, somewhat like 
Pine ‘foil the Woolwich beds ; others, containing more impurity, 
and some resembling Egyptian j jasper 
One flint pebble “pears the imperfect cast of a pecten, and in 
others are markings somewhat the en eg in appearance. One 
perforated by a tube about 2 inches long, containing a sabe 
core of light porous siliceous matter about ?” in diameter. 
In one case the flint has a sp. gr. of 2-586, and in another 2°570. 
bien tea —A pebble containing rolled fragments of white 
quartz, pale brown felspar, l crystals, and black 
asper or basalt, destained together by a black ferru ginous paste. 
Basalt.—In the form of a pebble of porphyritic structure, and 
containing large crystals of augite. Another specimen, in the 
form of an almost spherical pebble, broke with a sub-conchoidal 
fracture, and showed weathering for about 1” from outer surface. 
The specific gravity was low, ‘being only 3. 678. 
Porphyry.—Small pebble of a red colour, an intimate mixture 
of red orthoclase felspar and quartz, a little hornblende and mica 
present. The exterior of the stone is quite black, and probably 
like most of the others, was taken by Signor D’ Albertis from a 
fireplace 
Tron Pyrites.—In dark liver-coloured masses, showing radiate 
structure when broken open (Marcasite) ; in nee very like 
that from the Lias clay. Rapidly oxidizes to sulphate 
‘as scr on assaying to yield minute traces of ¢ ld. 
e form of nodules with a concentric seiner 
Some ab are hollow ‘ris others have a loose nucleus or kernel in 
side, and in flat cake like masses, of fair quality as an ore of iron. 
Also as bright red and yellow ochres—one specimen was in a 
calabash, and ‘the other wrapped in ti-tree — ready 
for use as pigments and personal adornmem 
ere are also specimens of ferruginous oe clays of red, 
brown, iy and grey colours, from the banks of the Katau and 
Fly Rivers 
Limestone.—Compact, somewhat crystalline, no fossils, weathered 
Ohitside - evidently from the sea shore, since one piece has an 
oyster shell attached. 
A fragme ae = hers oes aragonite, but blackened and saturated 
with tarry ma 
One rah apa mass was found to be hollow like a geode, and 
the cavity lined with inten quartz crys stals, 
Amongst the calcareous st bl le up of rolled 
Roane 
