In Part V of "Origins of the Celts," Hubert discusses "The Goidelic Cradle":
So when does he really answer the "where from?" question? Here:But whence did the Goidels come, and when did they come? Where must we look for their earliest home on the Continent and their starting-point? Probably they came from north of the Brythonic domain, and it is to them that tradition refers when it tells that the Celts used to live on the low coasts of the North Sea. They must have left those shores very early, for hardly a trace of them remains there (p. 169).
. . . In the first period of the Bronze Age there arrived in the British Isles, coming from the Continent, people with very marked characteristics. The old Neolithic inhabitants (among whom I include those of all the beginning of the Bronze Age) were long-heads of Mediterranean type, who built for their dead, or, at least, for the more distinguished of them, tumuli with a funeral chamber known as the "long barrows", in which one sometimes finds those curious bell-shaped beakers adorned at regular intervals with bands of incised or stamped decoration, of a very simple and austere type. The newcomers were of quite a different type, and had other funeral practices.
They buried their dead under round tumuli, known as "round barrows", in graves in which the body was placed in a crouching position on one side and enclosed in stone flags or woodwork. Later they burned them. In their graves there were zoned beakers (Fig. 33), but of a late type in which the neck is distinguished from the belly, or vases derived from these beakers . . . The grave goods comprised buttons with a V-shaped boring, flint and copper daggers, arrow-heads, and flat perforated pieces of schist which are "bracers", or bowman's wristguards. The skeletons were of a new type: tall, with round heads of a fairly constant shape, the brow receding, the supraciliary ridge prominent, the cheek-bones highly developed, and the jaws massive and projecting so as to present a dip at the base of the nose. I have already described them as one of the types represented in Celtic burials.
The association of the physical type of this people with the beaker has led British anthropologists to call it the Beaker Folk . . . In Scotland they were accompanied by other brachycephals, with a higher index and of Alpine type. In general they advanced from south to north and from east to west, and their progress lasted long enough for there to be a very marked difference in furniture between their oldest and latest tombs.
. . . Their progress was a conquest. It is evident that they subdued and assimilated the previous occupants of the country (pp. 171-173).
It is at least certain that the Beaker Folk went from Germany to Britain, and not from Britain to Germany. The typical round-heads of the round barrows are a Nordic type, which may have grown up on the plains of Northern Europe . . . Secondly, the similarity of the British barrows to the tumuli of North Germany at the beginning of the Bronze Age and the constant practice of burying the dead, when inhumation is practised, in a contracted position, as in Central Germany; and lastly, the similarity of many of the urns of the round barrows, which are late developments of the zoned beaker, and of other vases found there, to the so-called Neolithic pottery of North Germany in the region of the megaliths.
. . . At this point it is legitimate to ask what became of all the people who set up the megalithic monuments in the north-west of Germany, and what became of the tribes of bowmen who were mingled with them, for it is a dogma of German Siedelungsgeschichte that all the north-west seaboard, Westphalia, and Hanover were emptied of their inhabitants before the second period of the Bronze Age.
Many scholars, British, German, and French, have accordingly thought that the mixed population of this part of Germany, which one day set off and emigrated, was the original stock of the Goidels (pp. 175-176).
. . . The most obscure point in the hypothesis adopted is the original position of the future Goidels, for if the zone-beaker folk was the nucleus which organized them it is very hard to determine where it was itself formed. Moreover, it spread over almost the whole of the Celtic domain and left descendants there. In any case it occupied all the seaboard districts between the Rhine and the Elbe which remained outside the frontiers previously mentioned. These were the districts which were emptied by the migration of the Goidels to Britain.
. . . Was it a total or a partial emigration? It was probably partial, for there remained what is usually left behind by peoples which have been a long time in a country where they have been engaged in adapting the ground to human life, namely the distribution of dwellings and the shape of villages and fields. In the western part of North-Western Germany, in Western Hanover, and Westphalia, cultivated land and dwellings are arranged in a manner which is foreign to Germany, or has become so. It is the arrangement found in Ireland (Fig. 35), part of England, and France.
. . . Agricultural peoples never change their abode entirely. This is an indication that the Goidels did not leave in one body, and that they did not all leave.
What was the reason of their emigration? It was certainly not weakness or poverty. Perhaps there was some encroachment of the sea on a coast which has altered much. Perhaps some invention in the matter of navigation was discovered. The megalith builders whom the Goidels surrounded were certainly sailors who were not afraid of crossing the North Sea (pp. 187-188).