AND THE AVON GORGE. 
179 
the tongue-shaped Clifton Down, while the othei% somewhat 
further north, passes N.E. as Durdham Down, and then making 
a bold curve round Westburj, passes W. and_ a little S., along 
Henbury Down and King’s Weston Down, to end off at Penpole 
Point. Between Henbury Down and King’s Weston Down the 
ridge is deeply notched at Coomb Dingle, and through the notch 
runs the Henbury branch of the Trym. Within this horse-shoe 
ridge of Downs lies the lower, but never very low, land, through 
which the Trym makes its way to the Avon. 
On the Somersetshire side of the Avon there runs, at the 
foot of the more southerly slope of the Downs, a broken and 
discontinuous ridge, marked by tumps and wooded clumps, and 
continued, on the Gloucestershire side, by Brandon Hill and the 
ridge on which the University College stands. North of the 
ridge of Downs, on the other hand, runs a line of depression, 
the collecting ground of several streamlets, tributaries of the 
Avon, North of this, again, is a well-marked ridge curving 
round from Failands House through Abbot’s Leigh ; through this 
ridge the tributary streams cut deep notches. North of this 
once more is another somewhat discontinuous line of depression, 
where the tributary streams themselves receive minor tribu- 
taries. Finally, to the north of this is irregularly rising ground, 
through which the tributaries cut notch-like valleys to the Avon. 
Such, in brief, are the physical features of the area. Let 
us now see how far this physical configuration is dependent upon 
geological structure. 
4r.— -The Geological Structure of the area under consideration. 
The rocks in our area may be divided into two series, 
an older and a newer; whereof the new^er lie more or less 
horizontally on the upturned edges of the older, and occupy the 
depressions which resulted from a very ancient denudation. 
To begin wdth the older series. The broken ridge, of which 
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