IX 
STREAMS OF STONES 
207 
those found in the Silurian formations of Europe ; the hills are 
formed of white granular quartz rock. The strata of the latter 
are frequently arched with perfect symmetry, and the appear¬ 
ance of some of the masses is in consequence most singular. 
Pernety 1 has devoted several pages to the description of a Hill 
of Ruins, the successive strata of which he has justly compared 
to the seats of an amphitheatre. The quartz rock must have 
been quite pasty when it underwent such remarkable flexures 
without being shattered into fragments. As the quartz insensibly 
passes into the sandstone, it seems probable that the former 
owes its origin to the sandstone having been heated to such a 
degree that it became viscid, and upon cooling crystallised. 
While in the soft state it must have been pushed up through 
the overlying beds. 
In many parts of the island the bottoms of the valleys are 
covered in an extraordinary manner by myriads of great loose 
angular fragments of the quartz rock, forming “ streams of 
stones.” These have been mentioned with surprise by every 
voyager since the time of Pernety. The blocks are not water- 
worn, their angles being only a little blunted ; they vary in 
size from one or two feet in diameter to ten, or even more than 
twenty times as much. They are not thrown together into 
irregular piles, but are spread out into level sheets or great 
streams. It is not possible to ascertain their thickness, but the 
water of small streamlets can be heard trickling through the 
stones many feet below the surface. The actual depth is 
probably great, because the crevices between the lower fragments 
must long ago have been filled up with sand. The width of 
these sheets of stones varies from a few hundred feet to a mile ; 
but the peaty soil daily encroaches on the borders, and even 
forms islets wherever a few fragments happen to lie close 
together. In a valley south of Berkeley Sound, which some of 
our party called the “ great valley of fragments,” it was necessary 
to cross an uninterrupted band half a mile wide, by jumping 
from one pointed stone to another. So large were the fragments, 
that being overtaken by a shower of rain, I readily found 
shelter beneath one of them. 
Their little inclination is the most remarkable circumstance 
in these “streams of stones.” On the hill-sides I have seen 
1 Pernety, Voyage mix Isles Malouines , p. 526. 
