The Volcano relief is based on an illustration of the workings of a volcano taken from the book ‘Moses and Geology’. The book, published in 1883, was an attempt to explain the physical workings of our planet in the light of the Bible and so to counter the great advances in science that had been made earlier that century.
Excerpt from MOSES AND GEOLOGY: Or The Harmony Of The Bible With Sience by Samual Kinns
... ‘In the month of June, 1759, the cultivators of the farm began to be disturbed by strange subterranean noises of an alarming kind, accompanied by frequent shocks of earthquake, which continued for nearly a couple of months; but they afterwards entirely ceased, so that the inhabitants of the place were lulled into security. On the night between the 28th and 29th of September, however, the subterranean noises were renewed with greater loudness than before, and the ground shook awfully. The Indian servants living on the place started from their beds in terror, and fled to the neighbouring mountains. Thence gazing upon their master's farm, they beheld it, along with a tract of ground measuring between three and four square miles, raised up, as if it had been inflated from beneath like a bladder. At the edges this tract was uplifted about thirty-nine feet above the original surface, but so great was its convexity that towards the middle it attained a height of no less than 524 feet.
The Indians who beheld this strange phenomenon declared that they saw flames issuing from several parts of this elevated tract, and that the entire surface became agitated like a stormy sea. Great clouds of ashes, illuminated by volcanic fires glowing beneath them, rose at several points, and white-hot stones were thrown to an immense height. Vast chasms at the same time opened in the ground, and into these the two small rivers above mentioned plunged. Their waters, instead of extinguishing the subterranean conflagration, appeared only to add to its intensity.
Quantities of mud enveloping balls of basalt were now thrown up, and the surface of the elevated ground became studded with small cones, from which volumes of dense vapour, chiefly steam, were emitted, some of the jets rising from twenty to thirty feet in height. These cones the Indians called ovens, and in many of them is heard even now a subterranean noise resembling that of water briskly boiling.
Out of a great chasm in the midst of these ovens there were thrown up six larger elevations, the highest being 1,600 feet above the level of the plain, and now constituting the principal volcano of Jorullo, which has a regular volcanic crater, whence have been thrown up great quantities of stones and lava containing fragments of older rocks. The ashes emitted from the volcano were thrown to an immense distance, some of them having fallen on the houses at Queretaro, 150 miles from Jorullo.
How privileged were the men who saw one of these upheavals of the Earth’s crust! And though but a small matter compared with the rising of mountain-chains, yet it must have been strikingly grand to see a mountain springing up from the level ground, with all the attendant phenomena; and if they were believers in Revelation, how it must have convinced them of the truthfulness of the Biblical story, and the great power of the Creator in ordaining laws which should bring about similar results to those related by Moses!’ ...
(from: Moses and Geology, page 98)