257 
in the Valley of Coquimho. 
nor men, our estimates were made entirely by guess. This, 
however, does not affect the general question, but only the pro- 
portions. When at any time we found ourselves on one of these 
parallel roads, we saw, upon looking across the valley, or up or 
down it, as far as the eye could reach, portions of flat spaces, 
apparently on the same level with that on which we stood ; and 
when, in order to determine this more exactly, we went over the 
edge of the road or beach, and brought our eye into the plane 
of one of the roads, we invariably found, on looking round, that 
the same plane produced would merge into every portion of the 
same road, exactly as we should see the margin of a lake, with 
all its windings, on a level with the surface, if, while bathing, 
we were to bring the eye close to the water and look round. I 
regretted not having time to return with a spirit-level, to exa- 
mine this question of horizontality by infallible means. 
In the centre of the valley, which is six or seven miles wide, 
we found an extensive plane, narrow at the upper end, and 
widening out towards the sea, thus dividing the valley into two 
parts. This insulated space, was, to all appearance, quite flat 
and horizontal, and, as far as the eye could determine, exactly 
on a level with the highest of the above mentioned roads ; so 
that, if a lake ever stood in this valley, at the level of the road, 
the present surface must have been barely covered with water, 
or, as seamen term it, just lipping with the water’s edge. It is 
several miles wide, and shaped like a delta ; its sides are at 
many places deeply indented with ravines, which show it to be 
composed exclusively of the same water- worn materials as the 
roads ; and on both sides, the roads are easily traced at the same 
levels, and in perfect conformity with those on the opposite 
banks of the valley. The stones are principally granite and 
gneiss, with masses of shistus, whinstone, and quartz, mixed in- 
discriminately, and all bearing marks of having been worn by 
attrition under water. 
The theory which presents itself to explain these appearances, 
supposes a lake to have been formed, no matter how, and to 
stand at the level of the highest road, till a flat beach is produ- 
ced by stones being washed down from above. The water in this 
lake is next conceived to wear away, and break down a portion 
of the barrier ; this allows the lake to discharge part of its waters 
into the sea, and, consequently, lowers it to the second level ; 
vol. xi. no. 22 . oct. 1824 . 
E 
