soft sand.

"Twelve paces," he cried from the other side. "It's splendid; but I
wish it was a bit lighter. There must be somewhere for the light to
come in. Yes, I see!"

Vince pointed up at the side farthest from him where he stood, and a
little closer investigation showed that the pale soft light appeared to
be reflected upward against the roof, coming from behind a screen of
rock.

Crossing to this spot, they found that they could pass round the rocky
screen, which reached half-way to the ceiling, and they now stood in a
narrow passage lit by a soft green light, which came through a low arch,
and on reaching and passing through this the boys uttered a shout of
delight, for before them was another cavern of ample dimensions, whose
low flattened roof was glorious with a lovely, ever-changing pattern,
formed by the reflection of the sunlight from the waves outside. They
were fascinated for the time by the appearance of the roof, which seemed
to be all in motion--lights and shadows, soft as silken weavings,
chasing each other, opening, closing, and interlacing in the most
wonderful way, till they grew dazzled.

"It's too much to see at one time," whispered Mike at last. "I say!
look at the arch with ferns hanging all round like lace."

"Yes, and what a colour the sea is!"

"And the anemones and limpets and coral! Look at those pools, too,
among the rocks."

"Yes, and outside at the sea-birds. I say, Ladle! did you ever see
anything like it?"

"Never thought there was such a beautiful place in the world," replied
Mike softly. "Shall we go any farther?"

"Go any farther? I should think we will! Why, Mikey, this is all our
own! Two beautiful caverns, one opening into the other, and all a
secret, only known to ourselves. Talk about luck! But come on."

They passed under the arch, and stood in a cavern opening by another
arch upon the sea, which rippled and played amongst the sand below, the
mouth of the place being protected by ridge after ridge of rock just
level with the surface, and sufficient to break the force of the wild
currents, which boiled as they rushed by a short distance out. This
cavern appeared as if, at some distant period, it had been eaten out of
soft or half-decayed strata by the waves; and its peculiarity was the
great extent of low, fairly level roof, which in places the lads could
touch by tiptoeing and extending their fingers. It ran in at least a
hundred feet; and apparentl