"Another peculiarity is still more remarkable. Its higher or northern end consisted of a circular floor, 12 feet in diameter, covered with a dome of granite, two-thirds of which are still exposed to view; and my informant had observed a still greater portion of the dome-roofed chamber. Every successive layer of the stones forming the dome overhangs considerably the layer immediately beneath it; so that the stones gradually approach each other as they rise, until the top stones must originally have completed the dome; not, however, like the key-stones of an arch, but by resting horizontally on the immediately subjacent circular layer. The miner found no pottery, or anything else, in the cave. The height of the present wall of the dome is about 6 feet above the lowest part I could see; how much lower the original floor might have been, I could not ascertain.
"Another British cave, not even referred to in any publication, is to be seen at Chyoster, nearly three miles north of Penzance, the walls of which, instead of being perpendicular, are constructed on the same principle as the inmost part of the cave at Chapel Euny; so that the tops of these walls which support the huge slabs forming the roof, are much nearer each other than their bases. Each cave formed part of a British village, that of old Chyoster being decidedly in the best state of preservation of all the British villages in this neighbourhood."[2]
Both caves are built of uncemented stones unmarked by any tool. The cave at Chyoster extended originally, as appears from its remains and the rubbish left by its recent spoilers, fifty feet or more in a straight line up the sloping side of the hill. It is 6 feet high, 4 feet wide on the top, and 8 feet wide at the bottom, and is thought to have been originally a storehouse. It appears to have been built on the natural surface of the hillside, and then covered over with stones and earth, and planted with the evergreens which still abound there.
A few years subsequently to the above investigations, in one of those intellectual excursions by means of which our acquaintance with the early history of our island is so greatly extended, the following results were arrived at:--In the autumn of 1865, in an excursion made jointly by the Royal Institution of Cornwall and the Penzance Natural History Society, they inspected on the north coast of the county, Gurnard's Head, a rocky promontory, jutting some distance into the sea, and bearing very distinct traces of having been fortified by the early Britons against an enemy attacking from the sea, this being the only specimen of an ancient British fortification where traces of sea defences have been found. In all other cases they seem to have been erected as a protection from an attack by the land side, and to have been evidently the last retreat of the natives.