326 TlMEHRI. 
the rocks seem to have been less subjected to volcanic 
action than is the case immediately above and below. 
There is no doubt the country has been subjected at some 
period to an extraordinary upheaval, and large quantities 
of ironstone, both haematite and limonite, are everywhere 
met with, sometimes overlying the older igneous rocks 
and capping the more recent deposits, with which it is 
frequently intermingled. One curious feature to be met 
with in some of the placers, is the prevalence of lumps 
of conglomerate, in which are embedded many different 
kinds of rocks, the cementing principle being either silica 
or what looks like intensely hard, indurated clay. Out of 
one such lump I picked out a few small garnets and 
pieces of opalaceous quartz, as well as two or three 
small gold grains the size of a pin's head. 
The very dense forests prevailing over the entire 
country, and the absence of cliffs in any place, or sharp 
escarpments, where for a depth of many feet the structure 
of the earth's crust could be seen in section, preclude 
'any possibility of examining the rock formations ; and the 
question of the existence in the Puruni district of auri- 
ferous quartz veins, whose exploration would be remune- 
rative, cannot be superficially determined, but must 
depend largely on the striking of shafts and large outlay 
in machinery, food, and labour. 
There are no traces of glacial action such as fur- 
rows or polished surfaces to be found in the district ; 
though, in the beds of many of the streams, quartz and 
other pebbles can be seen rounded and even covered 
with scratches, which look like striae, inasmuch as they 
are mostly in the same direction as the line of their least 
resistance ; but curiously enough fragments of the same 
