hem that quite a wave rose and slightly
rocked the boat as the boys sat there awe-stricken, listening and
straining their eyes in the darkness which shut them in.

The noise occurred again--a great splash as of some mighty beast rearing
itself out of the water and letting itself fall back, followed by a
peculiar, wallowing noise.

This time it was lower and more as though it had passed the boat, and
directly after there was another splash, followed by a heavy beating
like something thrashing the water with its tail. Then came a
smothered, bellowing grunt as if the great animal had begun to roar and
then lowered its head half beneath the water, so that the noise was full
of curious gurglings. The flapping of the water was repeated, and this
time forty or fifty yards away, as near as they could guess, and once
more there was silence.

"I didn't know there were such horrible beasts as that in the water,"
whispered Rob.

"Nor I. What can it be?"

"Must have been big enough to upset the boat if it had seen us, or to
drag us out. Shall we wake Shaddy and ask him?"

"No," said Joe; "I don't suppose he would be able to tell us. It sounds
so horrible in the darkness."

"Why, I thought you were too much used to the river to be frightened at
anything."

"I did not say I was frightened," replied Joe quietly.

"No, but weren't you? I thought the thing was coming on right at the
boat."

"So did I," said Joe, very softly. "Yes, I was frightened too. I don't
think any one could help being startled at a thing like that."

"Because we could not see what it was," he continued thoughtfully. "I
fancied I knew all the animals and fish about the river, but I never
heard or saw anything that could be like that."

Just then they heard a soft, rustling sound behind, such, as might have
been made by a huge serpent creeping on to the boat; and as they
listened intently the sound continued, and the boat swayed slightly,
going down on one side.

"It's coming on," whispered Rob, with his mouth feeling dry and a
horrible dread assailing him, as in imagination he saw a huge scaly
creature gliding along the side of the boat and passing the covered-in
canvas cabin.

It was only a matter of moments, but it was like hours to the two boys.
The feeling was upon Rob that he must run to the fore-part, leap
overboard, and swim ashore, but he could not move. Every nerve and
muscle was paralysed, and when he tried to speak to his fell