疯狂山脉（IX）(3)

According to the carvings from which we had made our map, the desired tunnel-mouth could not be much more than a quarter-mile from where we stood; the intervening space shewing solid-looking buildings quite likely to be penetrable still at a sub-glacial level. The opening itself would be in the basement—on the angle nearest the foothills—of a vast five-pointed structure of evidently public and perhaps ceremonial nature, which we tried to identify from our aërial survey of the ruins. No such structure came to our minds as we recalled our flight, hence we concluded that its upper parts had been greatly damaged, or that it had been totally shattered in an ice-rift we had noticed. In the latter case the tunnel would probably turn out to be choked, so that we would have to try the next nearest one—the one less than a mile to the north. The intervening river-course prevented our trying any of the more southerly tunnels on this trip; and indeed, if both of the neighbouring ones were choked it was doubtful whether our batteries would warrant an attempt on the next northerly one—about a mile beyond our second choice.