In many parts of the island, the bottoms of the valleys
are covered in an extraordinary manner, by myriads of great
angular fragments of the quartz rock. These have been mentioned
with surprise by every voyager since the time of
Pernety. The whole may be called “ a stream of stones.”
The blocks vary in size, from that of a man’s chest to ten or
twenty times as large, and occasionally they altogether exceed
such measures. Their edges show no signs of being water-
worn, but are only a little blunted. They do not occur thrown
together in 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 could be heard
trickling through the stones many feet below the surface.
The actual depth is probably much greater, because the
crevices between the lower fragments must long ago have
been filled up with sand, and the bed of the rivulet thus
raised. The width of these beds varies from a few hundred
feet to a m ile ; hut 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 good shelter beneath
one of them.
Their little inclination is the most remarkable circumstance
in these “ streams of stones.” On the hiU-sides I have seen
them sloping at an angle of ten degrees with the horizon;
but in some of the level, broad-bottomed valleys, the inclination
is only just sufficient to be clearly perceived. On
so rugged a surface there was no means of measuring the
angle; but to give a common illustration, I may say that
the slope alone would not have checked the speed of an
English mail-coach. In some places, a continuous stream
of these fragments followed up the course of a valley, and
even extended to the very crest of the hill. On these
crests huge masses, exceeding in dimensions any small
building, seemed to stand arrested in their headlong course :
there, also, the curved strata of the archways lay piled
over each other, like the ruins of some vast and ancient
cathedral. In endeavouring to describe these scenes of
violence, one is tempted to pass from one simile to another.
We may imagine, that streams of white lava had flowed
from many parts of the mountains into the lower country,
and that, when consolidated, they had been rent by some
enormous convulsion into myriads of fragments. The expression,
“ streams of stones,” which immediately occurred
to every one, conveyed the same idea. These scenes are,
on the spot, rendered more striking, by the contrast of the
low, rounded forms of the neighbouring hills.
I was much interested by finding on the highest peak of one
range (about 7 0 0 feet above the sea) a great arched fragment,
lying on its convex or upper surface. Must we believe that
it was fairly pitched up in the air, and thus turned ? Or,
with more probability, that there existed formerly a part of
the same range more elevated than the point on which this
monument of a great convulsion of nature now lies. As the
fragments in the valleys are neither rounded nor the crevices
filled up with sand, we must infer that the period of violence
was subsequent to the land having been raised above the
waters of the sea. In a transverse section within these
valleys the bottom is nearly level, or rises but very little
towards either side. Hence the fragments appear to have
travelled from the head of the valley; but in reality it
seems most probable, either that they have been hurled
down from the nearest slopes, or that masses of rock were
broken up in the position they formerly occupied ; and that
since, by a vibratory movement of overwhelming force,* the
• “ N o u s n 'a v o n s p a s é té m o in s saisis d’é to n n em e n t à la v u e d e l ’in n
om b ra b le q u a n ti t é d e p ie r r e s d e to u te s g ra n d e u rs , b o u lev e rs é e s le s u n e s
su r les a u tr e s , e t c e p e n d a n t ran g é e s, c om m e si elle s a v o ie n t é té am o n c e lé e s
n é g lig em m e n t p o u r r em p lir des rav in s . O n n e s e la s so it p a s d ’a dm ir e r les
effets p ro d ig ie u x d e la n a tu r e .”— Pernety, p . 5 26.