r we have seen only the imaginative ideas of these great hollows of
the earth, for 'hollow' is the true meaning of the Latin word _cavea_,
from which cave or cavern is derived: now we will glance at the more
practical purposes to which the smaller and more superficial caves have
been adapted.

With the dawn of Christianity, many men and women, shocked at the
excesses of Greek and Roman civilisation, retired from the world and led
simple lives as hermits in remote caves. To this day, 'The Hermit's
Cave' is a common name in England, and, though it is not always a
genuine one, it usually denotes that in olden times some hermit or
'anchorite' passed his lonely existence in the spot in question.

Long before this era, in Hindoostan, advantage had been taken of natural
caverns to hew into shape the marvellous rock temples of Elephanta,
Ellora, and Ajunta, still accounted as amongst the wonders of the world.

In New Mexico and Arizona in remote ages whole tribes lived in caves,
some natural, but more often made habitable by the aid of masonry. Most
of these are high up on shelves edging precipitous cliffs, and were
clearly chosen as places of refuge from enemies of the plain.

All over Europe caves are found containing bones of human beings, most
of which are recognised by scientists to belong to an earlier race, who
made use of these homes provided by Nature, both for abiding-places
during life and resting-places for the dead. In many of these caves,
sketches on bone, horn, and ivory have been found, remarkable for their
clear and vigorous drawing at a time when art was an unknown quantity.
It is noticeable that drawings found amongst the Esquimaux relics depict
seals, whales, and walruses, whilst those of more southern races show
mammoths, wild horses, and bisons; the only animals drawn by both being
the reindeer.

Numerous caves in Britain, and indeed all over the world, contain bones
of animals, and from classifying these, learned folk have found out a
great deal respecting the geological and geographical changes which have
taken place on the crust of the earth since the Creation.

Now that we have thought of the terrors with which caverns inspired our
remote forefathers, as well as of the practical uses to which they have
been put by less imaginative men and animals, let us try to see how and
why these mighty hollows came to exist at all.

Earthquakes are often accountable for rocks heaped in wild confusion,
leavin