500 MR. \V. G. CLARKE ON THE MERES OF WRETHAM HEATH. 
water-level of the chalk. As this level rose, so would the water 
ascend and thus enlarge the areas until the basins were formed. 
Sir John Evans has noted that in Hertfordshire the chalk level of 
saturation has varied as much as seventy feet in the course of 
a single year. A process similar to that by which these meres 
were formed is even now going on in the neighbourhood of 
Thetford, and extensive subsidences have taken place. Mr. Bennett 
thought that the meres were fed by springs from the chalk at 
the same level, as they were all nearly the same height above the 
sea. Dr. J. E. lay lor said in 1871 that the meres dried up during 
drought, their water supply being simply the storage of the wet 
seasons. Dealing with the meres of Norfolk generally, he did not 
think many were fed by springs, because they were frequently 
active during seasons of drought. Mr. Robert Stevenson, the 
tenant of Fowlmere Farm, says he is certain that Fowlmere is fed 
by surface water and not by any spring. Later, we shall see in 
which direction the evidence tends. The fact that three of the 
more northerly meres contained, when drained, traces of the pile- 
dwellings of prehistoric man, proves that these pools have not been 
formed during the historic period. 
Ringmere. 
In the collection of Norse sagas known as the “ Heimskringla ” 
mention is made of a battle fought on “ Hringmar Heath,” probably 
in the year 1010 a.d. There appears to be no further mention of 
the spot until, in 1724, or the following year, Salmon, the author of 
“ Roman Stations ” saw a “ remarkable cavity called Ringmere Pit.” 
He said : — “ It is in the form of an amphitheatre to the bigness of 
six or seven acres with an uniform descent on every side to the 
arena. There was not in the latter end of October a drop of water 
in it, which the wet summer must have Idled if it had been a pond.” 
Writing in 1739, the Rev. Francis Blomefield said that there was 
in this nothing uncommon to those acquainted with it. It was 
generally full of water, he said, and the ground being a sand the 
water occasioned the uniform descent. He continued thus: — “It 
is supplied with landsprings from the adjacent hills (sic) which in 
the extreme dry year ceased running and so the water shrank into 
