Several times we noted the mouths of small lateral galleries not recorded in our diagrams; none of them such as to complicate the problem of our return, and all of them welcome as possible refuges in case we met unwelcome entities on their way back from the abyss.
The nameless scent of such things was very distinct. Doubtless it was suicidally foolish to venture into that tunnel under the known conditions, but the lure of the unplumbed is stronger in certain persons than most suspect—indeed, it was just such a lure which had brought us to this unearthly polar waste in the first place.
We saw several penguins as we passed along, and speculated on the distance we would have to traverse. The carvings had led us to expect a steep downhill walk of about a mile to the abyss, but our previous wanderings had shown us that matters of scale were not wholly to be depended on.
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 vapor 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 cloths 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 odor—of what nature we could not guess, though we thought of decaying organisms and perhaps unknown subterrane 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 débris, 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.