`Nonsense,' I said again, and we clambered down to the spot, and got between the upturned roots and the bank.

`Well?' he said.

But I did not answer this time. I only whistled. For there, laid bare by the removal of the earth, was an undoubted facing of solid stone laid in large blocks and bound together with brown cement, so hard that I could make no impression on it with the file in my shooting knife. Nor was this all; seeing something projecting through the soil at the bottom of the bared patch of walling, I removed the loose earth with my hands, and revealed a huge stone ring, a foot or more in diameter, and about three inches thick. This fairly staggered me.

`Looks rather like a wharf where good-sized vessels have been moored, does it not, Uncle Horace?' said Leo, with an excited grin.

I tried to say `Nonsense' again, but the word stuck in my throat-the ring spoke for itself. In some past age vessels had been moored there, and this stone wall was undoubtedly the remnant of a solidly constructed wharf. Probably the city to which it had belonged lay buried beneath the swamp behind it.

`Begins to look as though there were something in the story after all, Uncle Horace,' said the exultant Leo; and reflecting on the mysterious negro's head and the equally mysterious stonework, I made no direct reply.

`A country like Africa,' I said, `is sure to be full of the relics of long dead and forgotten civilisations. Nobody knows the age of the Egyptian civilisation, and very likely it had offshoots. Then there were the Babylonians and the Phoenicians, and the Persians and all manner of people, all more or less civilised, to say nothing of the Jews whom everybody "wants" nowadays. It is possible that they, or any one of them, may have had colonies or trading stations about here. Remember those buried Persian cities that the consul showed us at Kilwa.'²

`Quite so,' said Leo, `but that is not what you said before.'

`Well, what is to be done now?' I asked, turning the conversation.

As no answer was forthcoming we proceeded to the edge of the swamp, and looked over it. It was apparently boundless, and vast flocks of every sort of waterfowl came flying from its recesses, till it was sometimes difficult to see the sky.* Now that the sun was getting high it drew thin sickly looking clouds of poisonous vapour from the surface of the marsh and from the scummy pools of stagnant water.

`Two things are clear to me,' I said, addressing my three companions, who stared at this spectacle in dismay: `first, that we can't go across there' (I pointed to the swamp), `and, secondly, that if we stop here we shall certainly die of fever.'

`That's as clear as a haystack, sir,' said Job.

`Very well, then; there are two alternatives before us. One is to 'bout ship, and try and run for some port in the whale-boat, which would be a sufficiently risky proceeding, and the other to sail or row on up the river, and see where we come to.'

`I don't know what you are going to do,' said Leo, setting his mouth,' but I am going up that river.'

Job turned up the whites of his eyes and groaned, and the Arab murmured `Allah,' and groaned also. As for me, I remarked sweetly that as we seemed to be between the devil and the deep sea, it did not much matter where we went. But in reality I was as anxious to proceed as Leo. The colossal negro's head and the stone wharf had excited my curiosity to an extent of which I was secretly ashamed, and I was prepared to gratify it at any cost. Accordingly, having carefully fitted the mast, restowed the boat,