After about a quarter of a mile that nameless scent became greatly accentuated, and we kept very careful track of the various lateral openings we passed. There was no visible vapour as at the mouth, but this was doubtless due to the lack of contrasting cooler air. The temperature was rapidly ascending, and we were not surprised to come upon a careless heap of material shudderingly familiar to us. It was composed of furs and tent cloth taken from Lake’s camp, and we did not pause to study the bizarre forms into which the fabrics had been slashed. Slightly beyond this point we noticed a decided increase in the size and number of the side galleries, and concluded that the densely honeycombed region beneath the higher foothills must now have been reached. The nameless scent was now curiously mixed with another and scarcely less offensive odour – of what nature we could not guess, though we thought of decaying organisms and perhaps unknown subterranean fungi. Then came a startling expansion of the tunnel for which the carvings had not prepared us – a broadening and rising into a lofty, natural-looking elliptical cavern with a level floor, some seventy-five feet long and fifty broad, and with many immense side passages leading away into cryptical darkness.

Though this cavern was natural in appearance, an inspection with both torches suggested that it had been formed by the artificial destruction of several walls between adjacent honeycombings. The walls were rough, and the high, vaulted roof was thick with stalactites; but the solid rock floor had been smoothed off, and was free from all debris, detritus or even dust to a positively abnormal extent. Except for the avenue through which we had come, this was true of the floors of all the great galleries opening off from it; and the singularity of the condition was such as to set us vainly puzzling. The curious new fetor, which had supplemented the nameless scent, was excessively pungent here, so much so that it destroyed all trace of the other. Something about this whole place, with its polished and almost glistening floor, struck us as more vaguely baffling and horrible than any of the monstrous things we had previously encountered.

The regularity of the passage immediately ahead, as well as the larger proportion of penguin-droppings there, prevented all confusion as to the right course amidst this plethora of equally great cave mouths. Nevertheless we resolved to resume our paper trailblazing if any further complexity should develop; for dust tracks, of course, could no longer be expected. Upon resuming our direct progress we cast a beam of torchlight over the tunnel walls – and stopped short in amazement at the supremely radical change which had come over the carvings in this part of the passage. We realised, of course, the great decadence of the Old Ones’ sculpture at the time of the tunnelling, and had indeed noticed the inferior workmanship of the arabesques in the stretches behind us. But now, in this deeper section beyond the cavern, there was a sudden difference wholly transcending explanation – a difference in basic nature as well as in mere quality, and involving so profound and calamitous a degradation of skill that nothing in the hitherto observed rate of decline could have led one to expect it.