MR. W. G. CLARKE ON BRECKLAND CHARACTERISTICS. 565 
than these gravels, and representing the period when most of 
the fen plain was covered by brackish or tidal waters, dotted 
with more or less isolated patches of dry land.* Many of the 
present heaths and warrens of Breckland were thus post- 
glacial beaches and sand-dunes, and have retained a fauna 
and flora that is in some respects quite unique in England, for 
with the sea at its nearest point (the Wash) 18 miles distant 
from Methwold, various plants and insects typical of the 
sand-dunes still flourish, and nowhere else in England does 
the ringed plover breed inland. But though this distribution 
of fauna and flora probably originated in the post-glacial 
period, it is possible that a favourable influence in its per- 
petuation may have been exercised by the salt tides which, 
before the construction of the first Denver Sluice in 1652, 
regularly came up to Wilton Lode and doubtless to correspond- 
ing distances up the valleys of the Wissey and Lark, and 
would probably render the water brackish for some miles 
beyond. In a map of the Bedford Level in 1789 — kindly lent 
me by Mr. Arthur Bennett, F.L.S. — the north bank of the 
Little OuSe between Hockwold and the present Crosswater 
Staunch is marked as “ Sea Fenn.” There is also a tradition 
among the inhabitants of Hockwold that folks used to climb 
to the top of the church tower “ to see the ships across the 
fens.” Part of Methwold adjoining the fen is still known as 
“The Hythe ” ; the fen part of the Little Ouse is often 
called “Brand Creek,” and that of the Wissey” Hilgay Creek” ; 
and part of the heath between Barnham and Elveden was 
formerly called “ The Denes ” by agricultural labourers of 
the neighbourhood. 
At the present day the surface soil over most of the area is 
a thin layer of sand, in some parts covering boulder clay of 
no great thickness — the average depth being about 12 feet — 
and in others resting directly on the chalk. The sand varies 
in thickness from a few inches to several feet. When at least 
6 to 8 inches deep it is considered possible to cultivate it, 
but when very thick it absorbs moisture so rapidly as to be 
* Marr and Shipley’s ‘ Natural History of Cambridgeshire' (1902), p. 13S. 
VOL. VIII. 
P P 
