In the morning I ascended the rising ground at the back of Kalmanstunga, and thence obtained an interesting view over the country. In the foreground beneath Lang Jökull a long valley filled with lava from beyond Strutr stretches away from left to right; two rivers flow down the valley, one on each side of the lava, which determines their course along its edges. The Hvitá flowed on the edge of the lava just at the foot of the hills whereon I stood; on the far side of the valley, on the other edge of the lava, the Geitá flowed at the foot of the outlying hills of Lang Jökull. Away to the right in the valley between the two rivers, towards their confluence, I could see the denuded alluvium-covered lava noticed on the way. This alluvial matter is deposited during floods, when the waters of the swollen rivers unite and flow over the lava as one.
It was nearly mid-day before we got a start, for there had been delay over a very important matter. Jón had awakened me several hours earlier to inform me that there were no candles in the house! Now, candles would not seem to be a matter of much importance to us, considering that it was then broad daylight and that we had but little use for candles in the ordinary way, because daylight continued practically during the whole twenty-four hours; nor would the lack of them seem to be a thing to cause a delay in starting; but it was really the case, for we were about to proceed to the Surtshellir Caves, and candles were required to enable us to explore their passages. That being so, a messenger had to be sent to the farm-house at Husafell, where a stock was generally kept for anybody wanting to visit the caves. The caves were distant about two hours' ride—one rarely mentions distance in the ordinary way when travelling in Iceland, because ten miles, say, might represent a journey of three or four hours, or the same distance might be traversed in little more than an hour in very favourable ground. After crossing the rise at the back of Kalmanstunga, we descended into the valley of the Northingafljot, a clear-water river having its source in a number of lakes of glacial origin known as Fiskivötn, lying beyond Eyriks Jökull. The valley is filled with lava from the same source as that on the Hvitá side of Strutr, whence I had just come. Here the lava is noted for the number and extent of the caves that underlie it. There is a sharp rise as the river is ascended, the stream in consequence being a swift one—so swift, indeed, that it has been able to carve a way through the lava, which it crosses from one side of the valley to the other, a very unusual thing. The upper portion flows on the western edge of the lava and at the foot of the hills on that side; while the lower, after crossing the lava, flows along by the eastern edge at the foot of the mountains Strutr and Tunga.
THE NORTHINGAFLJOT CUTTING ACROSS THE LAVA.
The caves at Surtshellir are remarkable for several things. Their origin is probably due to a big bubble formation, helped partly, perhaps, by a crust of lava being forced upward in the form of an arch by pressure acting from the sides; though there is no doubt that they have been much enlarged and deepened by the eroding action of flowing water. An underground river used to flow through the caves, but as it does not do so now, some lower channel has doubtless been found. There was evidence of lower caves beneath those visited, for on stamping on the ground in several places, distinctly hollow sounds were produced. The falls into the Hvitá at Barnafoss, which are only a few miles away, lie in the Surtshellir line of drainage, and are proof that very large quantities of water are still flowing underground in this neighbourhood; in fact, it is highly probable that a great deal of water from the numerous lakes, the Fiskivötn, on Arnarvatnsheithi, escapes underground. There are two entrances to the caves—one near what is known as the Bone Cave, the other close by the Icicle Cave. The caves are in a picturesque spot, and beyond the entrance that we used there lies the great ice-covered Eyriks Jökull, one of the highest mountains in Iceland. There is a depression in the lava at this spot—a double depression, in fact, for inner and outer rims indicate them very distinctly, and it is obvious that the opening in the caves is due to the falling in of part of the roof. Access to the caves is obtained by scrambling down the loose broken lava to an opening at the bottom. The photographs do not give much idea of the roughness of the "going"; from end to end, except in the Icicle Cave, where difficulties of another kind were met with, the floor of the caves was strewn with broken lava. The fragments that have become detached from the roof and now lie upon the floor are angular blocks of extreme raggedness and hardness, piled up in confused heaps that test quality of boots, strength of ankles, and toughness (or tenderness) of skin, to say nothing of the mysterious capability of hanging on "by one's eyelids" that is almost absolutely necessary in places.
THE DOUBLE DEPRESSION IN THE LAVA AT THE ENTRANCE TO THE SURTSHELLIR CAVES.
