"This is a most extraordinary thing to find in the heart o' Australia," he said. "It's a tunnel driven through an enormous gold lode, an' it's vera evident that the men who made it knew almost nothing about mining, for the ore hasn't been stripped either to the hanging wall or foot wall. It's just as if a blind gap had been dug into the country where it was softest."
"I see a nugget shining in the roof," whispered Jack, pointing to a yellow splatch showing overhead.
"Ay, my lad, an' I can see several more," said Mackay, surveying the exposed stratum in bewilderment. "It is a wonderful mine, without a doubt, but what on earth the natives do with it is more than I can imagine."
He moved onwards once more, and then he halted suddenly, and held the candle aloft. The passage had come to an end; before him stood the huge stone panel which had first barred their entrance; at his feet gaped a deep, pit-like cavity.
"Come close up here, Bob," he said quietly. "Come an' have a look at this arrangement o' things; primitive but effective, eh?"
Bob gazed at the sight before him in absolute wonderment. The great stone which marked the end of the chamber stood upright on an egg-shaped base; it appeared to be formed like a rude and bluff wedge, the wider extremity protruding outwards, where, as had been seen, it flanged neatly on to the main rock from which it had sprung. But it was not its shape that surprised Bob: a massive bar of some gleaming metal was welded into it fully halfway up its height, and from this U-shaped bar a rope of extraordinary girth stretched taut into the depths of the pit, where it could be seen attached to a ponderous mass of diorite rock, which hung from it like the weight of a giant clock.
"It must take more than one man to open that door," murmured Jack.
"They probably always come in force when they use this passage," mused Bob; "and see, I suppose that arrangement is for keeping the stone bent over when they are out?"
He pointed to a short and stout log lying near, which had apparently been used for preventing a quick rush back of the weighted panel when the warriors had gone out on the night of the conflict. Mackay stepped gingerly across the intervening shaft, and shone his light into its unsavoury depths as he did so.