The next day was Tuesday, the 30th of June—and at six o'clock in the morning we resumed our journey.

We still continued to follow the gallery of lava, a perfect natural pathway, as easy of descent as some of those inclined planes which, in very old German houses, serve the purpose of staircases. This went on until seventeen minutes past twelve, the precise instant at which we rejoined Hans, who, having been somewhat in advance, had suddenly stopped.

"At last," cried my uncle, "we have reached the end of the shaft."

I looked wonderingly about me. We were in the centre of four cross paths—somber and narrow tunnels. The question now arose as to which it was wise to take; and this of itself was no small difficulty.

My uncle, who did not wish to appear to have any hesitation about the matter before myself or the guide, at once made up his mind. He pointed quietly to the eastern tunnel; and, without delay, we entered within its gloomy recesses.

Besides, had he entertained any feeling of hesitation it might have been prolonged indefinitely, for there was no indication by which to determine on a choice. It was absolutely necessary to trust to chance and good fortune!

The descent of this obscure and narrow gallery was very gradual and winding. Sometimes we gazed through a succession of arches, its course very like the aisles of a Gothic cathedral. The great artistic sculptors and builders of the Middle Ages might have here completed their studies with advantage. Many most beautiful and suggestive ideas of architectural beauty would have been discovered by them. After passing through this phase of the cavernous way, we suddenly came, about a mile farther on, upon a square system of arch, adopted by the early Romans, projecting from the solid rock, and keeping up the weight of the roof.

Suddenly we would come upon a series of low subterranean tunnels which looked like beaver holes, or the work of foxes—through whose narrow and winding ways we had literally to crawl!

The heat still remained at quite a supportable degree. With an involuntary shudder, I reflected on what the heat must have been when the volcano of Sneffels was pouring its smoke, flames, and streams of boiling lava—all of which must have come up by the road we were now following. I could imagine the torrents of hot seething stone darting on, bubbling up with accompaniments of smoke, steam, and sulphurous stench!

"Only to think of the consequences," I mused, "if the old volcano were once more to set to work."

I did not communicate these rather unpleasant reflections to my uncle. He not only would not have understood them, but would have been intensely disgusted. His only idea was to go ahead. He walked, he slid, he clambered over piles of fragments, he rolled down heaps of broken lava, with an earnestness and conviction it was impossible not to admire.

At six o'clock in the evening, after a very wearisome journey, but one not so fatiguing as before, we had made six miles towards the southward, but had not gone more than a mile downwards.

My uncle, as usual, gave the signal to halt. We ate our meal in thoughtful silence, and then retired to sleep.

Our arrangements for the night were very primitive and simple. A traveling rug, in which each rolled himself, was all our bedding. We had no necessity to fear cold or any unpleasant visit. Travelers who bury themselves in the wilds and depths of the African desert, who seek profit and pleasure in the forests of the New World, are compelled to take it in turn to watch during the hours of sleep; but in this region of the earth absolute solitude and complete security reigned supreme.

We had nothing to fear either from savages or from wild beasts.

After a night's sweet repose, we awoke fresh and ready for action. There being nothing to detain us, we started on our journey. We continued to burrow through the lava tunnel as before. It was impossible to make out through what soil we were making way. The tunnel, moreover, instead of going down into the bowels of the earth, became absolutely horizontal.

I even thought, after some examination, that we were actually tending upwards. About ten o'clock in the day this state of things became so clear that, finding the change very fatiguing, I was obliged to slacken my pace and finally come to a halt.

"Well," said the Professor quickly, "what is the matter?"

"The fact is, I am dreadfully tired," was my earnest reply.

"What," cried my uncle, "tired after a three hours' walk, and by so easy a road?"

"Easy enough, I dare say, but very fatiguing."

"But how can that be, when all we have to do is to go downwards."

"I beg your pardon, sir. For some time I have noticed that we are going upwards."

"Upwards," cried my uncle, shrugging his shoulders, "how can that be?"

"There can be no doubt about it. For the last half hour the slopes have been upward—and if we go on in this way much longer we shall find ourselves back in Iceland."

My uncle shook his head with the air of a man who does not want to be convinced. I tried to continue the conversation. He would not answer me, but once more gave the signal for departure. His silence I thought was only caused by concentrated ill-temper.

However this might be, I once more took up my load, and boldly and resolutely followed Hans, who was now in advance of my uncle. I did not like to be beaten or even distanced. I was naturally anxious not to lose sight of my companions. The very idea of being left behind, lost in that terrible labyrinth, made me shiver as with the ague.

Besides, if the ascending path was more arduous and painful to clamber, I had one source of secret consolation and delight. It was to all appearance taking us back to the surface of the earth. That of itself was hopeful. Every step I took confirmed me in my belief, and I began already to build castles in the air in relation to my marriage with my pretty little cousin.

About twelve o'clock there was a great and sudden change in the aspect of the rocky sides of the gallery. I first noticed it from the diminution of the rays of light which cast back the reflection of the lamp. From being coated with shining and resplendent lava, it became living rock. The sides were sloping walls, which sometimes became quite vertical.

We were now in what the geological professors call a state of transition, in the period of Silurian stones, so called because this specimen of early formation is very common in England in the counties formerly inhabited by the Celtic nation known as Silures.

"I can see clearly now," I cried; "the sediment from the waters which once covered the whole earth formed during the second period of its existence these schists and these calcareous rocks. We are turning our backs on the granite rocks, and are like people from Hamburg who would go to Lubeck by way of Hanover."

I might just as well have kept my observations to myself. My geological enthusiasm got the better, however, of my cooler judgment, and Professor Hardwigg heard my observations.

"What is the matter now?" he said, in a tone of great gravity.

"Well," cried I, "do you not see these different layers of calcareous rocks and the first indication of slate strata?"

"Well; what then?"

"We have arrived at that period of the world's existence when the first plants and the first animals made their appearance."

"You think so?"

"Yes, look; examine and judge for yourself."

I induced the Professor with some difficulty to cast the light of his lamp on the sides of the long winding gallery. I expected some exclamation to burst from his lips. I was very much mistaken. The worthy Professor never spoke a word.

It was impossible to say whether he understood me or not. Perhaps it was possible that in his pride—my uncle and a learned professor—he did not like to own that he was wrong in having chosen the eastern tunnel, or was he determined at any price to go to the end of it? It was quite evident we had left the region of lava, and that the road by which we were going could not take us back to the great crater of Mount Sneffels.

As we went along I could not help ruminating on the whole question, and asked myself if I did not lay too great a stress on these sudden and peculiar modifications of the earth's crust.

After all, I was very likely to be mistaken—and it was within the range of probability and possibility that we were not making our way through the strata of rocks which I believed I recognized piled on the lower layer of granitic formation.

"At all events, if I am right," I thought to myself, "I must certainly find some remains of primitive plants, and it will be absolutely necessary to give way to such indubitable evidence. Let us have a good search."

I accordingly lost no opportunity of searching, and had not gone more than about a hundred yards, when the evidence I sought for cropped up in the most incontestable manner before my eyes. It was quite natural that I should expect to find these signs, for during the Silurian period the seas contained no fewer than fifteen hundred different animal and vegetable species. My feet, so long accustomed to the hard and arid lava soil, suddenly found themselves treading on a kind of soft dust, the remains of plants and shells.

Upon the walls themselves I could clearly make out the outline, as plain as a sun picture, of the fucus and the lycopods. The worthy and excellent Professor Hardwigg could not of course make any mistake about the matter; but I believe he deliberately closed his eyes, and continued on his way with a firm and unalterable step.

I began to think that he was carrying his obstinacy a great deal too far. I could no longer act with prudence or composure. I stooped on a sudden and picked up an almost perfect shell, which had undoubtedly belonged to some animal very much resembling some of the present day. Having secured the prize, I followed in the wake of my uncle.

"Do you see this?" I said.

"Well, said the Professor, with the most imperturbable tranquillity, "it is the shell of a crustaceous animal of the extinct order of the trilobites; nothing more, I assure you."

"But," cried I, much troubled at his coolness, "do you draw no conclusion from it?"

"Well, if I may ask, what conclusion do you draw from it yourself?"

"Well, I thought—"

"I know, my boy, what you would say, and you are right, perfectly and incontestably right. We have finally abandoned the crust of lava and the road by which the lava ascended. It is quite possible that I may have been mistaken, but I shall be unable to discover my error until I get to the end of this gallery."

"You are quite right as far as that is concerned," I replied, "and I should highly approve of your decision, if we had not to fear the greatest of all dangers."

"And what is that?"

"Want of water."

"Well, my dear Henry, it can't be helped. We must put ourselves on rations."

And on he went.