Let us work our way back through past centuries and study our remote
ancestors on their first arrival upon earth; let us watch their early
struggles for existence! We will deal with facts alone; we will accept
no theories, and we must, alas, often fail to come to any conclusion,
for the present state of prehistoric knowledge rarely admits of
certainty. We must ever be ready to modify theories by the study
of facts, and never forget that, in a science so little advanced,
theories must of necessity be provisional and variable.

Truly strange is the starting-point of prehistoric science. It is with
the aid. of a few scarcely even rough-hewn flints, a few bones that
it is difficult to classify, and a few rude stone monuments that we
have to build up, it must be for our readers to say with what success,
a past long prior to any written history, which has left no trace in
the memory of man, and during which our globe would appeal to have
been subject to conditions wholly unlike those of the present day.

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]