If so, if this were true, away with the theories of Sir Humphry Davy; away with the authority of the parchment of Arne Saknussemm; the wonderful pretensions to discovery on the part of my uncle--and to our journey! All must end in smoke. Charmed with the idea, I began more carefully to look about me. A serious study of the soil was necessary to negative or confirm my hypothesis. I took in every item of what I saw, and I began to comprehend the succession of phenomena which had preceded its formation. Iceland, being absolutely without sedimentary soil, is composed exclusively of volcanic tufa; that is to say, of an agglomeration of stones and of rocks of a porous texture. Long before the existence of volcanoes, it was composed of a solid body of massive trap rock lifted bodily and slowly out of the sea, by the action of the centrifugal force at work in the earth. The internal fires, however, had not as yet burst their bounds and flooded the exterior cake of Mother Earth with hot and raging lava. My readers must excuse this brief and somewhat pedantic geological lecture. But it is necessary to the complete understanding of what follows. At a later period in the world's history, a huge and mighty fissure must, reasoning by analogy, have been dug diagonally from the southwest to the northeast of the island, through which by degrees flowed the volcanic crust. The great and wondrous phenomenon then went on without violence--the outpouring was enormous, and the seething fused matter, ejected from the bowels of the earth, spread slowly and peacefully in the form of vast level plains, or what are called mamelons or mounds. It was at this epoch that the rocks called feldspars, syenites, and porphyries appeared. But as a natural consequence of this overflow, the depth of the island increased. It can readily be believed what an enormous quantity of elastic fluids were piled up within its centre, when at last it afforded no other openings, after the process of cooling the crust had taken place. At length a time came when despite the enormous thickness and weight of the upper crust, the mechanical forces of the combustible gases below became so great, that they actually upheaved the weighty back and made for themselves huge and gigantic shafts. Hence the volcanoes which suddenly arose through the upper crust, and next the craters, which burst forth at the summit of these new creations. It will be seen that the first phenomena in connection with the formation of the island were simply eruptive; to these, however, shortly succeeded the volcanic phenomena. Through the newly formed openings, escaped the marvelous mass of basaltic stones with which the plain we were now crossing was covered. We were trampling our way over heavy rocks of dark grey color, which, while cooling, had been moulded into six-sided prisms. In the "back distance" we could see a number of flattened cones, which formerly were so many fire-vomiting mouths.