whicli the great river ruuiiiiig along the “ Deep Water Channel ” 
emptied itself. 
It may be in(|uired why I assume a higher elevation of Ilritain 
during the post glacial period. In the first place, I point to the 
ZTOlogical features common to this country, and those across the 
(channel, and to the fact that their community, and the possibility 
of migration hither could not have taken place until after the 
severe cold of the glacial period had passed away. The shallow- 
ness of the intervening sea is another indication of its recent 
origin. Lut 1 think we have, at Yarmouth, a very good proof of 
the land having stood higher subsc(iuent to the glacial period, and 
of the recent .severance of England from the Continent. Under- 
neath the Dene sands wo have a .stratum of recent estuarine 
deposits, to which my attention Wius kiiully dmwn by Mr. Fred. \V. 
llanner. These are one hundred and twenty feet in thickness, 
and therefore indicate the gradual depression of the land to that 
depth whilst they wore forming. They erpially jioint to the en- 
croachment of the Korth Sea over what were then the lowest 
lying lands, until the Cerman Ocean occujtied its jiresent site. 
As the latter process took place, we should have a gradual 
alteration in the arterial drainage of the next lowdying arca. The 
depression which took place whilst the Yarmouth estuarine deposits 
M-ere forming, had it continued, would have occupied the entire 
area of the Broad district, and thus produced a very diflerent 
coast line to the present. As the land gradually settled down to 
its present level, the hollower portions would then be filled with 
Avater, and become Broads. As a rule, these natural lakes are 
distinguished by always being connected with a river, either by 
means of a broad natural dyke, or by the river running through 
them. Most of them are hollowed out of the chalk, the erosion 
of which I spoke having cut away all the drift strata down to this 
parent rock. Surlingham, South AYalsham, AYroxham, Bamvorth, 
and many others, have all a chalk bottom. Over this there has 
accumulated a stratum of mud, which, in those Broads standin^r 
off the river, is very thick. ° 
In such places as the little Broad, at South Walsham, where 
there is a .scour l.y the current, the mud is absent, and the water 
in many places lift(>en feet .let>p. The deepest Broads are always 
those where the current is in action, ami the shallowest where it 
