"It has never been exactly ascertained," I replied, "whether the birds discover or produce this curious substance. But whatever may be its basis, it is clear that a very large portion of it is furnished by certain glands, which pour out a viscid secretion." "After laying in my store of nests," continued Fritz, "I pursued my way through this vaulted cave or corridor; which, presently turning, opened into a very lonely bay, so calm and lake-like, that, although of considerable size, I concluded at once it must be nearly land locked. Its shores, beyond the rocky boundary through which I penetrated, extended in a fertile plain toward what seemed the mouth of a river, beyond which lay rough, and probably marshy, ground, and a dense forest of cedars, which closed the view. "The water beneath me was clear as crystal; and, gazing into its depths and shallows, I perceived beds of shell-fish, like large oysters, attached to the rocks and to each other by tufts of hairy filaments. "'If these are oysters,' thought I, 'they must be better worth eating, as far as size goes, than our little friends in Safety Bay,' and thereupon I hooked up several clusters with my boat-hook, and landing soon after on the beach, I flung them on the sand, resolving to fetch another load, and then tow them after me in the fishing-net. "The hot sun disagreed with their constitution, I suppose; for when I came back the shells were all gaping wide open; so I began to examine them, thinking that after all they were probably much less delicate than the small oysters we have learnt to like so much. "Somehow, when a thing is to be 'examined,' one generally needs a knife. The blade met with resistance here and there in the creature's body; and still closer 'examination' produced from it several pearly balls like peas, of different sizes. Do you think they can be pearls? I have a number here in a box." "Oh, show them to us, Fritz!" cried the boys. "What pretty shining things! and how delicately rounded, and how softly they gleam!" "You have discovered treasure, indeed!" I exclaimed; "why these are most beautiful pearls! Valueless, certainly, under present circumstances; but they may prove a source of wealth, should we ever again come into contact with the civilized world. We must visit your pearl-oyster beds at the earliest opportunity." "After resting for some time, and refreshing myself with food," pursued Fritz, "I resumed my survey of the coast, my progress somewhat impeded by the bag of shell-fish, which I drew after me; but I proceeded without accident past the mouth of the stream to the further side of the bay, which was there inclosed by a point corresponding to that through which I had entered; and between these headlands I found a line of reefs and sandbanks, with but a single channel leading out to the open sea; from which, therefore, Pearl Bay, as I named it, lies completely sheltered.