But it was the mountainside tangle of regular cubes, ramparts, and cave mouths which fascinated and disturbed us most. I studied them with a field glass and took aerial photographs while Danforth drove; and at times I relieved him at the controls – though my aviation knowledge was purely an amateur's – in order to let him use the binoculars. We could easily see that much of the material of the things was a lightish Archaean quartzite, unlike any formation visible over broad areas of the general surface; and that their regularity was extreme and uncanny to an extent which poor Lake had scarcely hinted.

As he had said, their edges were crumbled and rounded from untold aeons of savage weathering; but their preternatural solidity and tough material had saved them from obliteration. Many parts, especially those closest to the slopes, seemed identical in substance with the surrounding rock surface. The whole arrangement looked like the ruins of Macchu Picchu in the Andes, or the primal foundation walls of Kish as dug up by the Oxford Field Museum Expedition in 1929; and both Danforth and I obtained that occasional impression of separate Cyclopean blocks which Lake had attributed to his flight-companion Carroll. How to account for such things in this place was frankly beyond me, and I felt queerly humbled as a geologist. Igneous formations often have strange regularities – like the famous Giants' Causeway in Ireland – but this stupendous range, despite Lake's original suspicion of smoking cones, was above all else nonvolcanic in evident structure.

The curious cave mouths, near which the odd formations seemed most abundant, presented another albeit a lesser puzzle because of their regularity of outline. They were, as Lake's bulletin had said, often approximately square or semicircular; as if the natural orifices had been shaped to greater symmetry by some magic hand. Their numerousness and wide distribution were remarkable, and suggested that the whole region was honeycombed with tunnels dissolved out of limestone strata. Such glimpses as we secured did not extend far within the caverns, but we saw that they were apparently clear of stalactites and stalagmites. Outside, those parts of the mountain slopes adjoining the apertures seemed invariably smooth and regular; and Danforth thought that the slight cracks and pittings of the weathering tended toward unusual patterns. Filled as he was with the horrors and strangenesses discovered at the camp, he hinted that the pittings vaguely resembled those baffling groups of dots sprinkled over the primeval greenish soapstones, so hideously duplicated on the madly conceived snow mounds above those six buried monstrosities.

We had risen gradually in flying over the higher foothills and along toward the relatively low pass we had selected. As we advanced we occasionally looked down at the snow and ice of the land route, wondering whether we could have attempted the trip with the simpler equipment of earlier days. Somewhat to our surprise we saw that the terrain was far from difficult as such things go; and that despite the crevasses and other bad spots it would not have been likely to deter the sledges of a Scott, a Shackleton, or an Amundsen. Some of the glaciers appeared to lead up to wind-bared passes with unusual continuity, and upon reaching our chosen pass we found that its case formed no exception.

Our sensations of tense expectancy as we prepared to round the crest and peer out over an untrodden world can hardly be described on paper; even though we had no cause to think the regions beyond the range essentially different from those already seen and traversed. The touch of evil mystery in these barrier mountains, and in the beckoning sea of opalescent sky glimpsed betwixt their summits, was a highly subtle and attenuated matter not to be explained in literal words. Rather was it an affair of vague psychological symbolism and aesthetic association – a thing mixed up with exotic poetry and paintings, and with archaic myths lurking in shunned and forbidden volumes. Even the wind's burden held a peculiar strain of conscious malignity; and for a second it seemed that the composite sound included a bizarre musical whistling or piping over a wide range as the blast swept in and out of the omnipresent and resonant cave mouths. There was a cloudy note of reminiscent repulsion in this sound, as complex and unplaceable as any of the other dark impressions.

We were now, after a slow ascent, at a height of twenty-three thousand, five hundred and seventy feet according to the aneroid; and had left the region of clinging snow definitely below us. Up here were only dark, bare rock slopes and the start of rough-ribbed glaciers – but with those provocative cubes, ramparts, and echoing cave mouths to add a portent of the unnatural, the fantastic, and the dreamlike. Looking along the line of high peaks, I thought I could see the one mentioned by poor Lake , with a rampart exactly on top. It seemed to be half lost in a queer antarctic haze – such a haze, perhaps, as had been responsible for Lake's early notion of volcanism. The pass loomed directly before us, smooth and windswept between its jagged and malignly frowning pylons. Beyond it was a sky fretted with swirling vapors and lighted by the low polar sun – the sky of that mysterious farther realm upon which we felt no human eye had ever gazed.

A few more feet of altitude and we would behold that realm. Danforth and I, unable to speak except in shouts amidst the howling, piping wind that raced through the pass and added to the noise of the unmuffled engines, exchanged eloquent glances. And then, having gained those last few feet, we did indeed stare across the momentous divide and over the unsampled secrets of an elder and utterly alien earth.

V

I think that both of us simultaneously cried out in mixed awe, wonder, terror, and disbelief in our own senses as we finally cleared the pass and saw what lay beyond. Of course, we must have had some natural theory in the back of our heads to steady our faculties for the moment. Probably we thought of such things as the grotesquely weathered stones of the Garden of the Gods in Colorado , or the fantastically symmetrical wind-carved rocks of the Arizona desert. Perhaps we even half thought the sight a mirage like that we had seen the morning before on first approaching those mountains of madness. We must have had some such normal notions to fall back upon as our eyes swept that limitless, tempest-scarred plateau and grasped the almost endless labyrinth of colossal, regular, and geometrically eurythmic stone masses which reared their crumbled and pitted crests above a glacial sheet not more than forty or fifty feet deep at its thickest, and in places obviously thinner.

The effect of the monstrous sight was indescribable, for some fiendish violation of known natural law seemed certain at the outset. Here, on a hellishly ancient table-land fully twenty thousand feet high, and in a climate deadly to habitation since a prehuman age not less than five hundred thousand years ago, there stretched nearly to the vision's limit a tangle of orderly stone which only the desperation of mental self-defense could possibly attribute to any but conscious and artificial cause. We had previously dismissed, so far as serious thought was concerned, any theory that the cubes and ramparts of the mountainsides were other than natural in origin. How could they be otherwise, when man himself could scarcely have been differentiated from the great apes at the time when this region succumbed to the present unbroken reign of glacial death?

Yet now the sway of reason seemed irrefutably shaken, for this Cyclopean maze of squared, curved, and angled blocks had features which cut off all comfortable refuge. It was, very clearly, the blasphemous city of the mirage in stark, objective, and ineluctable reality. That damnable portent had had a material basis after all – there had been some horizontal stratum of ice dust in the upper air, and this shocking stone survival had projected its image across the mountains according to the simple laws of reflection, Of course, the phantom had been twisted and exaggerated, and had contained things which the real source did not contain; yet now, as we saw that real source, we thought it even more hideous and menacing than its distant image.