i have said that our study of the decadent sculptures brought about a change in our immediate objective. this, of course, had to do with the chiseled avenues to the black inner world, of whose existence we had not known before, but which we were now eager to find and traverse. from the evident scale of the carvings we deduced that a steeply descending walk of about a mile through either of the neighboring tunnels would bring us to the brink of the dizzy, sunless cliffs about the great abyss; down whose sides paths, improved by the old ones, led to the rocky shore of the hidden and nighted ocean. to behold this fabulous gulf in stark reality was a lure which seemed impossible of resistance once we knew of the thing — yet we realized we must begin the quest at once if we expected to include it in our present trip.

it was now 8 p.m., and we did not have enough battery replacements to let our torches burn on forever. we had done so much studying and copying below the glacial level that our battery supply had had at least five hours of nearly continuous use, and despite the special dry cell formula, would obviously be good for only about four more — though by keeping one torch unused, except for especially interesting or difficult places, we might manage to eke out a safe margin beyond that. it would not do to be without a light in these cyclopean catacombs, hence in order to make the abyss trip we must give up all further mural deciphering. of course we intended to revisit the place for days and perhaps weeks of intensive study and photography — curiosity having long ago got the better of horror — but just now we must hasten.

our supply of trail-blazing paper was far from unlimited, and we were reluctant to sacrifice spare notebooks or sketching paper to augment it, but we did let one large notebook go. if worse came to worst we could resort to rock chipping — and of course it would be possible, even in case of really lost direction, to work up to full daylight by one channel or another if granted sufficient time for plentiful trial and error. so at last we set off eagerly in the indicated direction of the nearest tunnel.

according to the carvings from which we had made our map, the desired tunnel mouth could not be much more than a quarter of a mile from where we stood; the intervening space showing 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 aerial 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 southern tunnels on this trip; and indeed, if both of the neighboring 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.

as we threaded our dim way through the labyrinth with the aid of map and compass — traversing rooms and corridors in every stage of ruin or preservation, clambering up ramps, crossing upper floors and bridges and clambering down again, encountering choked doorways and piles of debris, hastening now and then along finely preserved and uncannily immaculate stretches, taking false leads and retracing our way (in such cases removing the blind paper trail we had left), and once in a while striking the bottom of an open shaft through which daylight poured or trickled down — we were repeatedly tantalized by the sculptured walls along our route. many must have told tales of immense historical importance, and only the prospect of later visits reconciled us to the need of passing them by. as it was, we slowed down once in a while and turned on our second torch. if we had had more films, we would certainly have paused briefly to photograph certain bas-reliefs, but time-consuming hand-copying was clearly out of the question.

i come now once more to a place where the temptation to hesitate, or to hint rather than state, is very strong. it is necessary, however, to reveal the rest in order to justify my course in discouraging further exploration. we had wormed our way very close to the computed site of the tunnel’s mouth — having crossed a second-story bridge to what seemed plainly the tip of a pointed wall, and descended to a ruinous corridor especially rich in decadently elaborate and apparently ritualistic sculptures of late workmanship — when, shortly before 8:30 p.m., danforth’s keen young nostrils gave us the first hint of something unusual. if we had had a dog with us, i suppose we would have been warned before. at first we could not precisely say what was wrong with the formerly crystal-pure air, but after a few seconds our memories reacted only too definitely. let me try to state the thing without flinching. there was an odor — and that odor was vaguely, subtly, and unmistakably akin to what had nauseated us upon opening the insane grave of the horror poor lake had dissected.

of course the revelation was not as clearly cut at the time as it sounds now. there were several conceivable explanations, and we did a good deal of indecisive whispering. most important of all, we did not retreat without further investigation; for having come this far, we were loath to be balked by anything short of certain disaster. anyway, what we must have suspected was altogether too wild to believe. such things did not happen in any normal world. it was probably sheer irrational instinct which made us dim our single torch — tempted no longer by the decadent and sinister sculptures that leered menacingly from the oppressive walls — and which softened our progress to a cautious tiptoeing and crawling over the increasingly littered floor and heaps of debris.

danforth’s eyes as well as nose proved better than mine, for it was likewise he who first noticed the queer aspect of the debris after we had passed many half-choked arches leading to chambers and corridors on the ground level. it did not look quite as it ought after countless thousands of years of desertion, and when we cautiously turned on more light we saw that a kind of swath seemed to have been lately tracked through it. the irregular nature of the litter precluded any definite marks, but in the smoother places there were suggestions of the dragging of heavy objects. once we thought there was a hint of parallel tracks as if of runners. this was what made us pause again.

it was during that pause that we caught — simultaneously this time — the other odor ahead. paradoxically, it was both a less frightful and more frightful odor — less frightful intrinsically, but infinitely appalling in this place under the known circumstances — unless, of course, gedney — for the odor was the plain and familiar one of common petrol — every-day gasoline.

our motivation after that is something i will leave to psychologists. we knew now that some terrible extension of the camp horrors must have crawled into this nighted burial place of the aeons, hence could not doubt any longer the existence of nameless conditions — present or at least recent just ahead. yet in the end we did let sheer burning curiosity — or anxiety — or autohypnotism — or vague thoughts of responsibility toward gedney — or what not — drive us on. danforth whispered again of the print he thought he had seen at the alley turning in the ruins above; and of the faint musical piping — potentially of tremendous significance in the light of lake’s dissection report, despite its close resemblance to the cave-mouth echoes of the windy peaks — which he thought he had shortly afterward half heard from unknown depths below. i, in my turn, whispered of how the camp was left — of what had disappeared, and of how the madness of a lone survivor might have conceived the inconceivable — a wild trip across the monstrous mountains and a descent into the unknown, primal masonry.

but we could not convince each other, or even ourselves, of anything definite. we had turned off all light as we stood still, and vaguely noticed that a trace of deeply filtered upper day kept the blackness from being absolute. having automatically begun to move ahead, we guided ourselves by occasional flashes from our torch. the disturbed debris formed an impression we could not shake off, and the smell of gasoline grew stronger. more and more ruin met our eyes and hampered our feet, until very soon we saw that the forward way was about to cease. we had been all too correct in our pessimistic guess about that rift glimpsed from the air. our tunnel quest was a blind one, and we were not even going to be able to reach the basement out of which the abyssward aperture opened.

the torch, flashing over the grotesquely carved walls of the blocked corridor in which we stood, showed several doorways in various states of obstruction; and from one of them the gasoline odor — quite submerging that other hint of odor — came with especial distinctness. as we looked more steadily, we saw that beyond a doubt there had been a slight and recent clearing away of debris from that particular opening. whatever the lurking horror might be, we believed the direct avenue toward it was now plainly manifest. i do not think anyone will wonder that we waited an appreciable time before making any further motion.

and yet, when we did venture inside that black arch, our first impression was one of anticlimax. for amidst the littered expanse of that sculptured crypt — a perfect cube with sides of about twenty feet — there remained no recent object of instantly discernible size; so that we looked instinctively, though in vain, for a farther doorway. in another moment, however, danforth’s sharp vision had descried a place where the floor debris had been disturbed; and we turned on both torches full strength. though what we saw in that light was actually simple and trifling, i am none the less reluctant to tell of it because of what it implied. it was a rough leveling of the debris, upon which several small objects lay carelessly scattered, and at one corner of which a considerable amount of gasoline must have been spilled lately enough to leave a strong odor even at this extreme superplateau altitude. in other words, it could not be other than a sort of camp — a camp made by questing beings who, like us, had been turned back by the unexpectedly choked way to the abyss.

let me be plain. the scattered objects were, so far as substance was concerned, all from lake’s camp; and consisted of tin cans as queerly opened as those we had seen at that ravaged place, many spent matches, three illustrated books more or less curiously smudged, an empty ink bottle with its pictorial and instructional carton, a broken fountain pen, some oddly snipped fragments of fur and tent cloth, a used electric battery with circular of directions, a folder that came with our type of tent heater, and a sprinkling of crumpled papers. it was all bad enough but when we smoothed out the papers and looked at what was on them, we felt we had come to the worst. we had found certain inexplicably blotted papers at the camp which might have prepared us, yet the effect of the sight down there in the prehuman vaults of a nightmare city was almost too much to bear.

a mad gedney might have made the groups of dots in imitation of those found on the greenish soapstones, just as the dots on those insane five-pointed grave mounds might have been made; and he might conceivably have prepared rough, hasty sketches — varying in their accuracy or lack of it — which outlined the neighboring parts of the city and traced the way from a circularly represented place outside our previous route — a place we identified as a great cylindrical tower in the carvings and as a vast circular gulf glimpsed in our aerial survey — to the present five-pointed structure and the tunnel mouth therein.

he might, i repeat, have prepared such sketches; for those before us were quite obviously compiled, as our own had been, from late sculptures somewhere in the glacial labyrinth, though not from the ones which we had seen and used. but what the art-blind bungler could never have done was to execute those sketches in a strange and assured technique perhaps superior, despite haste and carelessness, to any of the decadent carvings from which they were taken — the characteristic and unmistakable technique of the old ones themselves in the dead city’s heyday.

there are those who will say danforth and i were utterly mad not to flee for our lives after that; since our conclusions were now — notwithstanding their wildness — completely fixed, and of a nature i need not even mention to those who have read my account as far as this. perhaps we were mad — for have i not said those horrible peaks were mountains of madness? but i think i can detect something of the same spirit — albeit in a less extreme form — in the men who stalk deadly beasts through african jungles to photograph them or study their habits. half paralyzed with terror though we were, there was nevertheless fanned within us a blazing flame of awe and curiosity which triumphed in the end.

of course we did not mean to face that — or those — which we knew had been there, but we felt that they must be gone by now. they would by this time have found the other neighboring entrance to the abyss, and have passed within, to whatever night-black fragments of the past might await them in the ultimate gulf — the ultimate gulf they had never seen. or if that entrance, too, was blocked, they would have gone on to the north seeking another. they were, we remembered, partly independent of light.

looking back to that moment, i can scarcely recall just what precise form our new emotions took — just what change of immediate objective it was that so sharpened our sense of expectancy. we certainly did not mean to face what we feared — yet i will not deny that we may have had a lurking, unconscious wish to spy certain things from some hidden vantage point. probably we had not given up our zeal to glimpse the abyss itself, though there was interposed a new goal in the form of that great circular place shown on the crumpled sketches we had found. we had at once recognized it as a monstrous cylindrical tower figuring in the very earliest carvings, but appearing only as a prodigious round aperture from above. something about the impressiveness of its rendering, even in these hasty diagrams, made us think that its subglacial levels must still form a feature of peculiar importance. perhaps it embodied architectural marvels as yet unencountered by us. it was certainly of incredible age according to the sculptures in which it figured — being indeed among the first things built in the city. its carvings, if preserved, could not but be highly significant. moreover, it might form a good present link with the upper world — a shorter route than the one we were so carefully blazing, and probably that by which those others had descended.

at any rate, the thing we did was to study the terrible sketches — which quite perfectly confirmed our own — and start back over the indicated course to the circular place; the course which our nameless predecessors must have traversed twice before us. the other neighboring gate to the abyss would lie beyond that. i need not speak of our journey — during which we continued to leave an economical trail of paper — for it was precisely the same in kind as that by which we had reached the cul-desac; except that it tended to adhere more closely to the ground level and even descend to basement corridors. every now and then we could trace certain disturbing marks in the debris or litter underfoot; and after we had passed outside the radius of the gasoline scent, we were again faintly conscious — spasmodically — of that more hideous and more persistent scent. after the way had branched from our former course, we sometimes gave the rays of our single torch a furtive sweep along the walls; noting in almost every case the well-nigh omnipresent sculptures, which indeed seem to have formed a main aesthetic outlet for the old ones.

about 9:30 p.m., while traversing a long, vaulted corridor whose increasingly glaciated floor seemed somewhat below the ground level and whose roof grew lower as we advanced, we began to see strong daylight ahead and were able to turn off our torch. it appeared that we were coming to the vast circular place, and that our distance from the upper air could not be very great. the corridor ended in an arch surprisingly low for these megalithic ruins, but we could see much through it even before we emerged. beyond there stretched a prodigious round space — fully two hundred feet in diameter — strewn with debris and containing many choked archways corresponding to the one we were about to cross. the walls were — in available spaces — boldly sculptured into a spiral band of heroic proportions; and displayed, despite the destructive weathering caused by the openness of the spot, an artistic splendor far beyond anything we had encountered before. the littered floor was quite heavily glaciated, and we fancied that the true bottom lay at a considerably lower depth.

but the salient object of the place was the titanic stone ramp which, eluding the archways by a sharp turn outward into the open floor, wound spirally up the stupendous cylindrical wall like an inside counterpart of those once climbing outside the monstrous towers or ziggurats of antique babylon. only the rapidity of our flight, and the perspective which confounded the descent with the tower’s inner wall, had prevented our noticing this feature from the air, and thus caused us to seek another avenue to the subglacial level. pabodie might have been able to tell what sort of engineering held it in place, but danforth and i could merely admire and marvel. we could see mighty stone corbels and pillars here and there, but what we saw seemed inadequate to the function performed. the thing was excellently preserved up to the present top of the tower — a highly remarkable circumstance in view of its exposure — and its shelter had done much to protect the bizarre and disturbing cosmic sculptures on the walls.

as we stepped out into the awesome half daylight of this monstrous cylinder bottom — fifty million years old, and without doubt the most primally ancient structure ever to meet our eyes — we saw that the ramp-traversed sides stretched dizzily up to a height of fully sixty feet. this, we recalled from our aerial survey, meant an outside glaciation of some forty feet; since the yawning gulf we had seen from the plane had been at the top of an approximately twenty-foot mound of crumbled masonry, somewhat sheltered for three-fourths of its circumference by the massive curving walls of a line of higher ruins. according to the sculptures, the original tower had stood in the center of an immense circular plaza, and had been perhaps five hundred or six hundred feet high, with tiers of horizontal disks near the top, and a row of needlelike spires along the upper rim. most of the masonry had obviously toppled outward rather than inward — a fortunate happening, since otherwise the ramp might have been shattered and the whole interior choked. as it was, the ramp showed sad battering; whilst the choking was such that all the archways at the bottom seemed to have been recently cleared.

it took us only a moment to conclude that this was indeed the route by which those others had descended, and that this would be the logical route for our own ascent despite the long trail of paper we had left elsewhere. the tower’s mouth was no farther from the foothills and our waiting plane than was the great terraced building we had entered, and any further subglacial exploration we might make on this trip would lie in this general region. oddly, we were still thinking about possible later trips — even after all we had seen and guessed. then, as we picked our way cautiously over the debris of the great floor, there came a sight which for the time excluded all other matters.

it was the neatly huddled array of three sledges in that farther angle of the ramp’s lower and outward-projecting course which had hitherto been screened from our view. there they were — the three sledges missing from lake’s camp — shaken by a hard usage which must have included forcible dragging along great reaches of snowless masonry and debris, as well as much hand portage over utterly unnavigable places. they were carefully and intelligently packed and strapped, and contained things memorably familiar enough: the gasoline stove, fuel cans, instrument cases, provision tins, tarpaulins obviously bulging with books, and some bulging with less obvious contents — everything derived from lake’s equipment.

after what we had found in that other room, we were in a measure prepared for this encounter. the really great shock came when we stepped over and undid one tarpaulin whose outlines had peculiarly disquieted us. it seems that others as well as lake had been interested in collecting typical specimens; for there were two here, both stiffly frozen, perfectly preserved, patched with adhesive plaster where some wounds around the neck had occurred, and wrapped with care to prevent further damage. they were the bodies of young gedney and the missing dog.