otable examples are the
building of the pebbly beaches of Chesil Bank and near Treguier in Cotes
du Nord, and the promontory of Dungeness. The total drainage area of the
English rivers flowing into the Channel is about 8000 sq. m.; of the
French rivers, including as they do the Seine, it is about 41,000 sq. m.

From the Strait of Dover the bottom slopes fairly regularly down to the
western entrance of the Channel, the average depths ranging from 20 to
30 fathoms in the Strait to 60 fathoms at the entrance. An exception to
this condition, however, is found in Hurd's Deep, a narrow depression
about 70 m. long, lying north and north-west of the Channel Islands, and
at its nearest point to them only 5 m. distant from their outlying
rocks, the Casquets. Towards its eastern end Hurd's Deep has an extreme
depth of 94 fathoms, and in it are found steeper slopes from shoal to
deep water than elsewhere within the Channel. Nearing the entrance to
the Channel from the Atlantic, the 100 fathoms line may be taken to mark
the edge of soundings. Beyond this depth the bottom falls away rapidly.
The 100 fathoms line is laid down about 180 m. W. to 120 m. S.W. of the
Scilly Isles, and 80 m. W. of Ushant. Within it there are considerable
irregularities of the bottom; thus a succession of narrow ridges running
N.E. and S.W. occurs west of the Scillies, while only 4 m. N.W. of
Ushant there is a small depression in which a depth of 105 fathoms has
been found. As a general rule the slope from the English coast to the
deepest parts of the Channel is more regular than that from the French
coast, and for that reason, and in consideration of the greater dangers
to navigation towards the French shore, the fairway is taken to lie
between 12 and 24 m. from the principal promontories of the English
shore, as far up-channel as Beachy Head. These promontories (the Lizard,
Start Point, Portland Bill, St Alban's Head, St Catherine's Point of the
Isle of Wight, Selsey Bill, Beachy Head, Dungeness, the South Foreland)
demarcate a series of bays roughly of sickle-shape, the shores of which
run north and south, or nearly so, at their western sides, turn eastward
somewhat abruptly at their heads, and then trend more gently towards the
south-east. On the French coast the arrangement is similar but reversed;
Capes Grisnez, Antifer and La Hague, and the Pointe du Sillon
demarcating a series of bays (larger than those on the English coast)
whose shores run north an