All at once the rocky passage terminated abruptly in a medium sized chamber with a high roof. The air in here was cool and pleasant, and the boys sat down to rest on a rock while they looked about them in the rays of the pocket lamp.
"This is a queer sort of place to stumble on," mused Jack; "wonder if anyone ever explored it before."
"I dinna ken," rejoined Sandy, "but, mon, I can spy another openin' yonder. Suppose that when we are rested we see what is beyant."
"Very well," agreed Jack readily. "As far as that goes, I'm ready to start right now."
Sandy declared that he was rested too, and the lads crossed the rocky chamber and plunged into another passage on the other side. It was similar in character to the tunnel through which they had entered the big cavern, except that its downward slope was pitched still more steeply.
"I wonder where on earth this is going to lead us?" ruminated Jack as they trudged along.
"We must ha' come more than half a mile noo," grunted out Sandy.
"Tired?" asked Jack.
"A little."
"Well, we might as well turn back then. I don't think it's much use our keeping on any further."