which it came in contact.
It may even have been a mixed race to start with. Thus even if we found
skulls of very different types in the dolmens this would not in the
least disprove the idea that dolmen building was introduced into various
countries by one and the same race. It would be simply a case of the
common anthropological fact that a race immigrating into an already
inhabited country becomes to some extent modified by intermarriage with
the earlier inhabitants. The measurements given in the last chapter
would seem to show that despite local variation there is an underlying
homogeneity in the skulls of the megalithic people.

It thus seems that the most probable theory of the origin of the
megalithic monuments is that this style of building was brought to the
various countries in which we find it by a single race in an immense
migration or series of migrations. It is significant that this theory
has been accepted by Dr. Duncan Mackenzie, who is perhaps the first
authority on the megalithic structures of the Mediterranean basin.

One question still remains to be discussed. From what direction did
megalithic architecture come, and what was its original home? This is
clearly a point which is not altogether dependent on the means by which
this architecture was diffused. Montelius speaks in favour of an Asiatic
origin. He considers that caves, and tombs accessible from above, i.e.
simple pits dug in the earth, were native in Europe, while tombs reached
from the side, such as dolmens and corridor-tombs, were introduced into
Europe from the east. Salomon Reinach, arguing mainly from the early
appearance of the objects found in the tombs of Scandinavia and the
rarity of the simpler types of monument, such as the dolmen, in Germany
and South Europe, suggests that megalithic monuments first appeared in
North Europe and spread southwards. Mackenzie is more inclined to
believe in an African origin. If he is right it may be that some
climatic change, possibly the decrease of rainfall in what is now the
Sahara desert, caused a migration from Africa to Europe very similar to
that which many believe to have given to Europe its early neolithic
population. The megalithic people may even have been a branch of the
same vast race as the neolithic: this would explain the fact that both
inhumed their dead in the contracted position.

It is probable that the problem will never be solved. The only way to
attempt a solution would be t