28 PROCEEDINGS COTTESWOLD CLUB 1901 
Ist. The land considerably higher in relation to sea 
level than it is at present; much denudation of the Severn 
Valley.” 
2nd. Subsidence of the land and deposit of the blue 
estuarine clay, No. 2 in Section. The vertical limit of this 
subsidence I am unable to state from want of data: in> 
Lancashire and Cheshire it was the 25 feet contour. 
3rd. Re-emergence of land and elevation above its present 
level and growth of forest trees, as represented by the 
Superior Peat and Forest-Bed. It is impossible to measure 
the extent of this elevation, but judging by the develop- 
ment of this Forest-bed all round the British Isles, it pro- 
bably amounted to several hundred feet. 
Ath. Re-submergence of this forest margin with its 
river valleys extending considerably below low-water 
mark. Deposit of tidal alluvium as represented by bed 
No. 5. (The Bruges Canal deposit, Belgium, is an 
equivalent.)” 
Perhaps some will consider these deductions rather 
venturesome and founded on insufficient data. In explana- 
tion I may say that I have been studying these deposits for 
1 In this connection a valuable paper by T. Codrington, M.I.C.E., “On some Sub- 
merged Rock- hee in South Wales, Devon and Cornwall,” (Quart. Journ. Geol. Soc., 
Vol. liv., pp. 251-278 ; 1898) should be studied. 
2 See “ Post-Glacial Beds exposed in the cutting of the New Bruges Canal.” (Q.J.G.S., 
Vol. liv. pp. 575-581; 1898), In connection with this last depression of the land, Mr. 
G. W. Keeling, the Engineer to the Gloucester Harbour Board, has very kindly supplied 
me with some interesting information as to the movement of the tidal waters of the 
Severn at Westbury, which I give in his own words :— 
« An ordinary spring tide would be about 25-75 ft. above Ordnance Datum, and the 
highest equinoctial spring tide about 28°75. 
“At this part of the river the direction and velocity of the wind affects the height 
of the tide more than the freshets, and both combined cause abnormal high tides, such 
as occurred Feb. 12th, 1899, when the tide at Westbury rose to about 32-00 above O.D. 
“The vertical range of the tide at Westbury would be on ordinary spring tides 
about 14 feet, and in equinoctial tides about 3 feet more. 
«The abnormal tides referred to in No. 2 sometimes overtop the sea walls and flood 
the adjoining land, but otherwise the high tides simply flood the alluvial lands between 
the sea walls and ordinary high-water mark. 
“The water is very saline at spring tides and very much less so at neap tides. In fact 
some low neap tides barely reach Westbury.” 
