458 EH. E.. L. Dixon—Titterstone Clee Hills. 
contained a tremendous volume of water, which being confined by the 
Carboniferous ranges in the east and probably dammed by ice on the 
north would fill the channel to a considerable depth. The 500 feet 
contour-line was well above the line of principal lake-deposition, and 
probably the 400 feet line or a line between this and 300 feet limited 
the margin of the lake or series of lakes. The deposits at the higher 
elevations, while continuous with those confined to the 300 feet 
contour limit, are undoubtedly composed of material less water-worn. 
The coarse gravels in the sections near Wooler and Roddam were the 
littoral deposits, while the finer material and sands of Hedgeley were 
carried into the quiet and deeper portion of the lake. 
The alluvial tracts of the Breamish and other streams, the peat and 
marl-like deposits of the recent lake-basins were formed after the 
supply of water to the mountain torrents had diminished but was still 
very much in excess of their present supply. 
EXPLANATION OF PLATE XXXY. 
Fic. 1. The Breamish Valley below Low Hedgeley. In the foreground, rising above 
the alluvial plain, are deposits of sand. The Carboniferous ridges are seen in 
the distance. 
Fic. 2. Section of sand and gravel exposed by Wooler Water near Haugh Head, 
Wooler. 
V.—Tue Gronocy or tae Tirrersrone Crier Hits.) 
By E. EH. L. Drxon, B.Se., A.R.C.S., F.G.S. 
\HE following is a preliminary account of the rocks overlying the 
Lower Old Red Sandstone of the Titterstone Clee Hills, Shrops. 
Sedimentary Series . . 4. Coal-Measures. 
3. Millstone Grit (so-called). 
2. Carboniferous Limestone Series. 
1. Upper Old Red Sandstone. 
: Intrusive rocks . é ¢ Dolerite. 
1. The Upper Old Red Sandstone, consisting largely of sandy and 
pebbly beds, is fixed in age by its fish- fauna, which has long been 
known. Its junction with the underlying Lower Old Red matls is 
perfectly sharp, and probably marks an unconformity. Upwards, 
however, the group passes into— 
2. The Carboniferous Limestone Series. The correlation of the local 
development with the Avonian of other districts has been sketched by 
Dr. Vaughan,” whose chief conclusion, that the highest recognizable 
horizon is little, if at all, higher than the upper part of the Zaphrentis 
Zone, holds good throughout the outcrops. That part of the series 
which overlies this horizon is so thin that it is difficult to believe that 
the top is much younger, even after making allowance for the fact 
that it consists of such shallow-water deposits that its rate of deposition 
must. have been conditioned by the rate of subsidence of the sea- 
bottom. This conclusion as to age is supported by the age and 
relations to the local ‘Millstone Grit’ of the top of the Carboniferous 
Limestone Series in the Forest of Dean and the Bristol area (op. cit.). 
1 Abstract of paper read at the British Association, Sheffield, September, 1910. 
2 Quart. Journ. Geol. Soc., vol. Ixi, pp. 252-4, 1905. 
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