Note 2 — Chapter I · The Stone Age: its Duration and its Place in Time.
N. D'Anvers translation
The stones which will first claim our attention, some of them very skilfully cut and carefully polished, have been known for centuries. According to Suetonius, the Emperor Augustus possessed in his palace on the Palatine Hill a considerable collection of hatchets of different kinds of rock, nearly all of them found in the island of Capri, and which were to their royal owner the weapons of the heroes of mythology. Pliny tells of a thunder-bolt having fallen into a lake, in which eighty-nine of these wonderful stones were soon afterwards found.2 Prudentius represents ancient German warriors as wearing gleaming ceraunia on their helmets; in other countries similar stones ornamented the statues of the gods, and formed rays about their heads.3