Page 100 - The snake's pass

88 THE SNAKE S PASS.
" Of course
! If my theory is correct, the shifting is
due to them."
"
" Explain
!
" So far as I can. But here I am only on surmise,
or theory pure and simple. I may be all wrong, or I
may be right—I shall know more before I am done with
Shleenanaher. My theory is that the shifting is due
to the change in the beds of clay, as for instance by
rains washing them by degrees to lower levels—this is
notably the case in that high clay bank just opposite
the Snake's Pass. The rocks are fixed, and so the clay
becomes massed in banks between them, perhaps aided
in the first instance by trees falling across the chasm
or opening. But then the perpetually accumulating
water from the spring has to find a way of escape ; and
as it cannot cut through the rock it rises to the earth
bed, till it either tops the bed of clay which confines it
or finds a gap or fissure through which it can escape.
In either case it makes a perpetually deepening channel
for itself, for the soft clay yields little by little to the
stream passing over it, and so the surface of the outer
level falls, and the water escapes, to perhaps find new
reservoirs ready made to receive it, and a similar pro-
cess as before takes place."
" Then the bog extends and the extended part takes
the place of the old bog which gradually drains."
" Just so ! but such would of course depend on the
level; there might be two or more reservoirs, each with
a deep bottom of its own and united only near the