A research study suggested that the skulls had been deliberately deposited without their lower jaws and that the discolouration of the bone suggested that they had been exposed for some time after death. However, excavations in the northern cemetery at Eldon Street (ELD88), adjacent to an upper tributary of the Walbrook, have found that some of the bodies had been washed out from their resting place and into the Walbrook itself and this may account for the skulls being found exposed in the stream bed.
The whole practice of skull deposition may be associated with a pre-Roman cult of the head, an ancient custom dating back to the late Bronze Age, which continued long into the Roman period. As well as skulls deposited in streams, a human skull was found deposited after a well in Queen Street (GM144) had silted up. There are numerous accounts of other finds of skulls, both human and animal, in Romano-British wells and their magical power is recorded in many Celtic legends.
The concentration of skulls in the area of the Upper Walbrook valley is mirrored by the distribution of ceramic face pots. The remains of over 100 pots have been found from London, making it one of the largest groups in the country.
These distinctive vessels originated in the Rhineland and appear to have been introduced to Britain by the Roman army. Most of the complete pots from London, mainly made in the St Albans area, have been found in the Walbrook valley and may have come from local shrines as ritual deposits.
The deposition of a statue head may be a continuance of the cult. The severed bronze head of the emperor Hadrian was found in the Thames in 1834.
Other finds of bronze arms and hands indicate a repetitive pattern that points to the observance of some ritual. Whatever its purpose, it overruled the recycling of valuable scrap metal into the melting pot. The uncorroded condition of the surviving examples, especially the condition of a gilded bronze arm (pictured far right), found at Gresham Street (GHT00 and see Emperor's left hand? in Londinium Lite), indicate that they must have come from waterlogged deposits such as wells or ponds and may have also been offered to lay the spirits of the statues to rest.
For more information about deposits in the Walbrook, see also Personal beliefs.