458 
me that no trophies or memorials of Kett’s rebellion had ever been 
found on Monsehold. 
Kesidences were also constructed on lakes, of which instances 
have been brought to light in cleaning out two of the meres at 
Wretham.'*'" These habitations were formed of mud and boughs, 
resting on platforms that were raised above the water by means of 
oaken piles. 
We must not neglect to notice the more important physical 
changes that took place during the time that man was improving 
the face of the country. 
The land, which stood at a higher level than it does now, must 
have slowly subsided to its present level, and this depression would 
of course tend to arrest further deepening of the river-channels, 
except in the higher parts of the courses. The rivers would, how- 
ever, widen when they could no longer deepen their channels ; the 
tendency of a stream to flow in a serpentine course, owing, perhaps, 
to local sources of deviation, causing it to act directly now on one 
side, and then on the other side of the valley. The streams would 
become more sluggish, and deposit material in sheltered places where 
the water had not velocity to hold it in suspension. 
Moreover, the depression allowed the sea to flow in, and enlarge 
the mouths of the streams, and in time to produce the extensive 
estuarine flats that extend from Yarmouth to Acle and Eeedham — 
flats that were afterwards rescued from the sea by the formation of 
the sand bank on Avhich Yarmouth now stands, and which did not 
exist previous to a.d. 1000. 
The subsidence just alluded to would cause the rivers to flood the 
entire breadth of the valleys they may previously have excavated 
by degrees and during many changes of course, while the estuarine 
waters would help to erode and to carry away material. In 
this way we may discern the seemingly very recent origin of 
our broads. 
These shallow freshwater lakes, excepting Breydon near Yarmouth, 
which is brackish, occur in the lower reaches of the Ykare and Bure; 
only one, that of Oulton, occurs in the Waveney valley. In the 
Waveney valley there is a good deal more valley gravel than in 
* Sir C. Bunbury, Quart. Journ. Geol. Soc. vol. xii. p. 355 ; Prof. A. Newton, 
‘ On the Zoology of Ancient Europe ’ (8vo. London, 1862), pp. 16—23. 
