ON ANCIENT CAMPS AND EARTH-WORKS. 115 
by a high mound and ditch. The date of this work is 
probably about 776 a.D., and that of Watt’s Dyke about 
twenty years earlier. This latter was broken through by 
an irruption of the people of Monmouthshire and Gla- 
morganshire, and replaced by Offa’s Dyke. There is pro- 
bably a space of 1,000 years between the date of the 
construction of Wansdyke and Offa’s Dyke, but boundary- 
lines of this nature seem to have been formed at all 
periods of the ancient history of our island. Thus, for 
instance, Dr. Guest in his discourse at the meeting of the 
Arch. Inst., at Cambridge, in 1854, in treating of the 
four great boundary-dykes of Cambridgeshire, considered 
them to be the boundary-lines of British princes. The 
Brent Dyke he assigned to the second period of the great 
Belgie Conquest, about B.c. 90, and the Pampisford Dyke 
to about A.D. 30. The Fleam Dyke and Devil’s Dyke are 
much later, the former being probably the Saxon lines of 
East Anglia in the war of the 7th century, between the 
Mercians and East Anglians, whilst the latter may be a 
Danish work of the close of the 9th century.* 
Wansdyke, although so much earlier than Offa’s Dyke, 
is a finer construction, the ditch deeper, the mound more 
elevated and abrupt. It is, however, inferior in these 
respects to Fleam Ditch and Devil’s Ditch, in the county 
of Cambridge. Both of these latter works, however, were 
for the purposes of defence, and fortified the ground be- 
tween two fens, or between a fen and a forest. Their 
length is very trifling compared to Wansdyke. The 
Devil’s Ditch does not extend further than eight miles, and 
might therefore be kept continually guarded. The Fleam 
Ditch extends nine and a quarter miles. The Devil’s 
* See Archxological Journal, No. 44, p. 395. 
