Georgius[258] Agricola draws a distinction between the _Brontia_ and the _Ceraunia_. The former, he says, is like the head of a tortoise, but has stripes upon it, the latter is smooth and without stripes. The _Brontia_ seems to be a fossil echinus, and the _Ceraunia_ a stone celt, but both are thunderbolts. Going a little further back, we find Marbodæus,[259] Bishop of Rennes, who died in the year 1123, and who wrote a metrical work concerning gems, ascribing the following origin and virtues to the _Ceraunius_:—— “Ventorum rabie cum turbidus æstuat äer, Cum tonat horrendum, cum fulgurat igneus æther, Nubibus elisus cœlo cadit ille lapillus. Cujus apud Græcos extat de fulmine nomen: Illis quippe locis, quos constat fulmine tactos, Iste lapis tantum reperiri posse putatur, Unde κεράυνιος est Græco sermone vocatus: Nam quod nos fulmen, Græci dixere κεραυνὸν. Qui caste gerit hune à fulmine non ferietur, Nec domus aut villæ, quibus affuerit lapis ille: Sed neque navigio per flumina vel mare vectus, Turbine mergetur, nec fulmine percutietur: Ad causas etiam, vincendaque prælia prodest, Et dulces somnos, et dulcia somnia præstat.” It was not, however, purely from the belief of his own day that Marbodæus derived this catalogue of the virtues of the Cerauniæ, but from the pages of writers of a much earlier date. Pliny,[260] giving an account of the precious stones known as Cerauniæ, quotes an earlier author still, Sotacus, who, to use the words of Philemon Holland’s translation, “hath set downe two kinds more of Ceraunia, to wit, the blacke and the red, saying that they do resemble halberds or axeheads. And by his saying, the blacke, |65| such especially as bee round withall, are endued with this vertue, that by the meanes of them, cities may be forced, and whole navies at sea discomfited; and these (forsooth) be called[261] Betuli, whereas the long ones be named properly Cerauniæ.” Pliny goes on to say, “that there is one more Ceraunia yet, but very geason[262] it is, and hard to be found, which the Parthian magicians set much store by, and they only can find it, for that it is no where to bee had than in a place which hath been shot with a thunderbolt.” There is a very remarkable passage in Suetonius[263] illustrative of this belief among the Romans. After relating one prodigy, which was interpreted as significant of the accession of Galba to the purple, he records that, “shortly afterwards lightning fell in a lake in Cantabria and twelve axes were found, a by no means ambiguous omen of Empire.” The twelve axes were regarded as referring to those of the twelve lictors, and were therefore portentous; but their being found where the lightning fell would seem to have been considered a natural occurrence, except so far as related to the number. It appears by no means improbable that if the lake could be now identified, some ancient pile settlement might be found to have existed on its shores.