known as Sundersley Gap, and was used principally, when used at all, by
the farmers' carts which came down to gather seaweed after a gale.

"What a magnificent stretch of sand!" continued Thorndyke, as we reached
the bottom, and stood looking out seaward across the deserted beach.
"There is something very majestic and solemn in a great expanse of
sandy shore when the tide is out, and I know of nothing which is capable
of conveying the impression of solitude so completely. The smooth,
unbroken surface not only displays itself untenanted for the moment, but
it offers convincing testimony that it has lain thus undisturbed through
a considerable lapse of time. Here, for instance, we have clear evidence
that for several days only two pairs of feet besides our own have
trodden this gap."

"How do you arrive at the 'several days'?" I asked.

"In the simplest manner possible," he replied. "The moon is now in the
third quarter, and the tides are consequently neap-tides. You can see
quite plainly the two lines of seaweed and jetsam which indicate the
high-water marks of the spring-tides and the neap-tides respectively.
The strip of comparatively dry sand between them, over which the water
has not risen for several days, is, as you see, marked by only two sets
of footprints, and those footprints will not be completely obliterated
by the sea until the next spring-tide--nearly a week from to-day."

"Yes, I see now, and the thing appears obvious enough when one has heard
the explanation. But it is really rather odd that no one should have
passed through this gap for days, and then that four persons should have
come here within quite a short interval of one another."