A WELSH BARD IN WILTSHIRE: IOLO MORGANWG, SILBURY AND THE SARSENS 81 
2002).’ The main significance of the excavation lies 
in the long-term side-effects attributed to poor or 
non-existent backfilling. This has until recently 
been assumed to be the cause of the structural 
problems which culminated in the major collapse at 
the Hill in May 2000.? It is this collapse that lends 
relevance to any new information about the 
excavation, and thanks to Iolo and his shepherd 
there is now more that can be said. There was, for 
example, no known date for the end of the dig, 
which could conceivably have been extended over 
two seasons. The letter gives us a new terminus ad 
quem of 12 January 1777; Iolo’s actual visit to the 
site could well have been a week or weeks before he 
wrote the letter — he implies, for example, that he 
has been delayed by frost — so the excavation must 
have taken place over November and December 
1776. ‘Some months’ is not an unreasonable 
description of the time period involved. 
We also have the suggestion that there were 
four, rather than the previously reported three, 
miners, which would make sense: David Field 
(pers. comm. 2002) has suggested that two were 
digging and two removing spoil. And, in 
‘Kingswood Coalmines’ we have a new and 
persuasive point of origin to add to earlier claims 
Watercolour by William Owen Pughe (1759-1835). Reproduced by kind permission of the National Library of Wales 
that they came from ‘Cornwall’ or ‘the Mendips’ 
(Field, Brown and Thomason, 2002, 16)* In other 
areas Iolo provides new information about the 
activities that took place, which included 
measuring the base of the hill and examining how it 
was built: ‘it was found to consist of chalk and 
gravel thrown together by the hands of men’ — a 
reasonably accurate description, even if it does not 
do full justice to the complexity of the hill’s internal 
engineering as it is now understood. But perhaps 
the most intriguing aspect of Iolo’s report is the 
statement that ‘there were many cavities in it but 
for what purpose is unknown as nothing was found 
in them’. 
The suggestion that there might be ancient 
cavities in the hill raises old questions: from the 
earliest times, observers have wondered if the hill 
conceals a burial or other structure. Yet no evidence 
for anything of this nature has been found in the 
three hundred years of archaeological investigation 
at Silbury Hill; and all known cavities appear to be 
the result of poorly-consolidated excavation. Even 
the role of the 1776 excavation is currently open to 
question: all the cavities revealed in Cementation 
Skanska’s seismic and geo-technical surveys in 
2001, 2002 and 2003 seem either to be anomalies in 
