June 19th. In order to pursue my journey without interruption, I hired fresh horses, and allowed my own, which were rather fatigued, to accompany us unloaded. My object in this further excursion was to visit the very remarkable cavern of Surthellir, distant a good thirty-three miles from this place. The clergyman was again kind enough to make the necessary arrangements for me, and even to act as my Mentor on the journey. Though we were only three strong, we departed with a retinue of seven horses, and for nearly ten miles rode back the same way by which I had come from Reikholt on the preceding morning; then we turned off to the left, and crossing hills and acclivities, reached other valleys, which were partly traversed by beautiful streams of lava, and partly interspersed with forests--_forests_, as I have already said, according to Icelandic notions. The separate stems were certainly slightly higher than those in the valley of Thingvalla. At Kalmannstunga we left the spare horses, and took with us a man to serve as guide in the cavern, from which we were now still some seven miles distant. The great valley in which this cavern lies is reckoned among the most remarkable in Iceland. It is a most perfect picture of volcanic devastation. The most beautiful masses of lava, in the most varied and picturesque forms, occupy the whole immeasurable valley. Lava is to be seen there in a rough glassy state, forming exquisite flames and arabesques; and in immense slabs, lying sometimes scattered, sometimes piled in strata one above the other, as though they had been cast there by a flood. Among these, again, lie mighty isolated streams, which must have been frozen in the midst of their course. From the different colours of the lava, and their transitions from light grey to black, we can judge of the eruptions which have taken place at different periods. The mountains surrounding this valley are mostly of a sombre hue; some are even black, forming a striking contrast to the neighbouring jokuls, which, in their large expanse, present the appearance almost of a sea of ice. I found one of these jokuls of a remarkable size; its shining expanse extended far down into the valley, and its upper surface was almost immeasurable. The other mountains were all smooth, as though polished by art; in the foreground I only noticed one which was covered with wonderful forms of dried lava. A deathlike silence weighed on the whole country round, on hill and on valley alike. Every thing seemed dead, all round was barren and desert, so that the effect was truly Icelandic. The greater portion of Iceland might be with justice designated the "Northern Desert."