It is very premature, however, to speculate either on these analogies or on the negative results of the explorations made into the hill: these last were undertaken, like the diggings at Avebury, on the empirical assumption that the principal deposit would be found in the centre, and at Silbury on the ground level, which is exactly the place where almost certainly it was not. Supposing that there is a low-level sepulture at Silbury, it probably will be found within 30 or 40 yards of the outer face of the mound, on the side looking towards Avebury, if it is connected with that monument. But the knowledge we have acquired, as will be afterwards detailed, from the examination of the Minning Lowe, Arbor Lowe, Rose Hill tumuli, and other monuments of this class, would lead us to expect to find the principal deposit near the summit. The bit of a bridle (woodcut No. 18) and the traces of armour which were found in Stukeley's time, near the summit, mark in all probability the position of the principal graves, and nothing would surprise me less than if five or six entombments were found arranged around the upper plateau at a small depth below the surface. We shall be in a better position to judge how far this is probable when we have finished this chapter; but till the evidence is adduced, it is useless to speculate on its effect. [Illustration: 18. Iron Bit of Bridle. Found in Silbury Hill.] At one time I hoped that the Roman road might be found to have passed under the hill, and if this were the case, it would settle the question as to whether it were pre- or post-Roman. In order to ascertain this, some excavations were made into the hill in 1867, and simultaneously on the high ground to the southward of it. As traces which seemed undoubtedly to mark the existence of the road running past the hill, at about 50 to 100 yards to the southward, were found there, the excavations into the hill were discontinued, and the line of the road considered as established. Owing to various mishaps, no plan of these discoveries has yet been published, but the annexed woodcut, which is traced from the Ordnance Survey sheet, will suffice to explain its bearing on the question. [Illustration: 19. Plan of Avebury, from Ordnance Survey. The line of the Roman road is hatched throughout.]