Though this question of cremation may appear to have slight connection with the use of coffins, a little study will show that there is a bond of association. The ashes of the dead were, it is true, usually enshrined in a cinerary urn, and this vessel was often placed in a chamber specially constructed for the purpose. But it was the coffin which was essentially a receptacle for preserving the entire body, and which therefore became the sign of earth-burial. Dr Rock lays down the rule that bishops, kings, and persons of rank were interred in stone coffins, while the bulk of the people had coffins of wood. Whenever the receptacle was made of wood, and not of stone, one might have supposed that it would readily become an accessory in the rite of cremation. This was apparently not the case, though, obviously, proof would be difficult to obtain. The body seems to have been burnt in an open pyre, not enclosed in a chest. Contrariwise, in a Saxon cemetery at Sibertswold, in Kent, ninety-nine of the coffins had been “submitted to the fire,” the bodies themselves being unburnt. Again, in the early Christian burials a cist of stones, instead of a coffin, was sometimes placed around the corpse[682], but there was no reversion to the funeral pyre. Yet, as already noticed, the employment, in isolated instances, of rude coffins, to say nothing of the cists by which they were foreshadowed, was probably in some measure contemporary with the general pagan custom of burning the dead. There was an overlapping of custom. Such seeming anachronisms, while they puzzle, do not greatly surprise the archaeologist, to whom such occurrences are no new feature. He frequently sees remote traces of the beginnings of a practice of which the general adoption was long delayed; he observes rites and customs overlapping in time and struggling for victory; and, in his own day, he is a witness of extraordinary vestiges and of ceremonies which must be deemed reversions or “throw-backs.” The overstepping of one burial rite by another of older origin is not a whit more inexplicable than the contemporaneous use, by man, of diverse kinds of clothes or of varying types of habitation. It is perhaps the more difficult problem to determine, in the absence of additional data, why, at a particular period, one group of men is found dwelling in pile-houses on the margins of lake or mere, while another class frequents caves and rock-shelters, and a third prefers the wattled hut with sunken floor, and roof of reeds or heather. Convenience was doubtless a partial cause of these diversities, just as belief was the great regulator of burial customs, but this is not the full answer. We must look to primary race distinctions, in which were the germs of the variations, and to the fact that human immigrations to Britain occurred at intervals, so that mental as well as physical territories were invaded and transgressed.