when he said that
the direct trail was not one that a laden pack-horse could travel with
ease, far less speed.

The earlier portion of the march was easy enough. But after about an
hour's walking through the bush the travellers reached a mile of
bogland, across which a path could only be found by stepping cautiously
from one grassy hummock to another. Even then the surface of the moss
shivered for yards around, and the mud between the tufts oozed, as if
its mouth were watering to swallow up the trio.

"Feel for every step before you put your weight on it!" the naturalist
instructed. He, of course, had taken the foremost position of leader.
"If you want to disappear quicker than you did in yon muskeg, Master
Bob, you can set the tip o' your big toe in yon mud, and you'll travel
as quick as electricity."

This part of the journey was certainly fatiguing, but the travellers
kept up good hearts by pleasant banter and dogged determination.

Reaching solid ground again, there was another easier spell of bush
tramping. Then the trail began the ascent of a hill--a rocky,
loose-bouldered slope that could only be traversed by a narrow path that
somewhat resembled a strip of ribbon on the side of a house.

Up they went, higher and higher each step, with the sharp slope to the
left and a sheer declivity of loose stones at the right.

Once Alf slipped, and the stone against which he tripped went leaping
down the slope without stopping, until it was lost to sight some three
hundred feet or more below.

"Which of you two laddies is the one that's danced down the hillside?"
questioned Mackintosh, without seeming to look round. His voice was
pleasant, but he had taken a quick glance backwards all the same, and
his face had paled a little. That was but his kindly way of cheering the
boys and helping them to keep their nerves in hand.

After a time the climbing ceased. It was now a level path, though it was
none the less ready to trap the unwary, as it twisted round spurs and
crossed little ravines. Then suddenly the travellers became aware of a
sound like that of a small cataract.

Mackintosh stopped, and as they listened they were able to tell that the
sound was one that proceeded from the continuous rolling of innumerable
stones that were being propelled down the hillside at no great distance.

"What on earth is it?" questioned Alf, and at the same moment the man
pointed towards a cloud of dust that had rounded a spur ahead