Page 102 - The snake's pass

90 THE SNAKE'S PASS.
of gap or canon in the rock formation, easily forming
it into a reservoir. Then if the barrier between the two
upper ones were to be weakened, and a sudden weight
of water were to be thrown on the lower wall ; suppose
such wall were to partially collapse, and bring down, say,
a clay bank, which would make a temporary barrier
loftier than any yet existing, but only temporary ; sup-
pose that the quick accumulation of waters behind this
barrier lifted the whole mass of water and slime and bog
to its utmost height. Then, when, such obstruction had
been reached, the whole lower barrier, weakened by infil-
tration and attacked with sudden and new force, would
give way at once, and the stream, kept down from above
by the floating bog, would force its way along the bed
rock and lift the whole spongy mass resting on it. Then
with this new extent of bog suddenly saturated and
weakened—demoralized as it were—and devoid of re-
sisting power, the whole floating mass of the upper bog
might descend on it, mingle with it, become incor-
porated with its semi-fluid substance, and form a new
and dangerous quagmire incapable of sustaining solid
weight, but leaving behind on the higher level only the
refuse and sediment of its former existence—all the
rubble and grit too heavy to float, and which would
gradually settle down on the upper bed rock."
" Eeally, Dick, you put it most graphically. What a
terrible thing it would be to live on the line of such
a change."
" Terrible, indeed At such a moment a house in the
!