A word may be said as to the relation of these Aryan invaders to the presumably non-Aryan aborigines, the Neolithic men to whom allusion was previously made. It used to be supposed that these aborigines disappeared before the men of bronze and iron as completely as the aborigines of Tasmania have disappeared before the Anglo-Saxon immigrant. More careful investigation has led our recent ethnologists to deny this conclusion. In the first place, there are features in the rude polity of the historic Celts which suggest a doubt whether they really constituted the whole population of the country. Their chiefs are warlike leaders, their rank and file are themselves owners of slaves. Everything about them seems to show that they were, like the Spartans, a comparatively small ruling race surrounded by a subject population, which they perhaps needed to keep severely in check. Then the testimony of the tombs--and it is after all to the tombs that we must chiefly resort for information as to the fate of these buried peoples--decidedly confirms the theory of the survival of the aborigines and of their blending to a considerable extent with their Celtic conquerors. The stone-using people buried their dead in oblong mounds technically known as “long barrows” generally some one hundred to two hundred feet long by forty or fifty feet wide. The skulls found in these long barrows, lying side by side with implements of stone, are uniformly of the type known as Dolicho-cephalic, that is, the width from ear to ear is very considerably less than the length from the eyes to the back of the head. With the introduction of bronze we at once find a noticeable difference both in the shape of the tomb and the appearance of its occupant. The mound is now circular, generally from forty to sixty feet in diameter, the “round barrow” of the archæologist; and the skulls found in it are at first uniformly of the Brachy-cephalic type, square and strong, the width generally about four-fifths of the length. The important point to observe for our present purpose is that as we pass from the early Celtic to the late Celtic type of barrow--a transition of which we are assured by the gradual introduction of iron as well as by other signs known to archæologists--the character of the skulls undergoes a certain modification towards the Dolicho-cephalic type. The conclusion arrived at by the greatest investigator of British barrows, Dr. Greenwell, is that “ultimately the two races became so mixed up and connected as to form one people. If this was the case, by a natural process the more numerous race would in the end absorb the other, until at length, with some exceptions to be accounted for by well-known laws, the whole population would become one, not only in the accidents of civilisation and government, but practically in blood also.” CHAPTER II. CÆSAR IN BRITAIN.