912 PROFESSOR J. PRESTWICH ON THE EVIDENCES OF A SUBMERGENCE 
upheavals, besides some minor ones in bed No. 2. This agrees, as a whole, perfectly 
well with the Brighton and Sangatte sections, where fine marly beds predominate 
in the central division, with coarse beds below and above, the last one evidently 
resulting from a stronger joi’opulsion and exercising greater erosive action. 
This section strengthens the conclusion forced upon us by the coast sections that 
the upheaval was not one continuous and uniform movement, but a succession of 
movements of greater or lesser rapidity, irregular in their action and not long 
prolonged. By prolonged, I mean continuous movements but of variable rapidity. 
If there were rests, they did not last long enough to leave marks of shore-wear at 
these successive stages on the upraised land. That there were pauses is shovni by 
the division of the beds in fig. 4, but they could not have been of long duration. 
The Normandy Coast. —Between the Somme valley and Havre the coast presents 
a line of chalk cliffs, closely resembling in all their features those between Brighton 
and Eastbourne. Like as on those parts of our coast, where the encroachment of 
the sea has removed the raised beach and left only detached trails of the rubble-drift 
in the valleys, so on the French coast the erosion of the cliffs, which may be estimated 
at 1 to 2 feet annually,* has removed all traces of the beach; but of the rubble-drift 
which overlaid the beaches and ascended higher inland, considerable portions remain 
in the bed and at the mouth of the valleys of Treport, Fecamp, and Etretat. This 
drift also contains at places remains of the extinct Mammalia. At Mers it consists 
of a mass of loam with chalk-and-flint rubble, as at Freshwater. It is probable 
also that the great bank of flint shingle or gravel from 12 to 18 feet thick which lies 
off the Pointe du Houdel, near St. Valery, and extends along the coast for a distance 
of about 10 miles, at a height of 16 feet above high tide, originated with the rubble- 
drift of the Somme valley. At St. Adresse, near Havre, the rubble-drift appears to 
be represented by a bed of slightly subangular flint gravel forming a low cliff extend¬ 
ing to the foot of the chalk hills, and connected by a thin trail with the chalk of the 
hills and with the red clay with flints which caps them. 
Six miles to the westward of Cherbourg a “ head,” 25 feet thick, of large angular 
fragments of the local granitic rocks in a matrix of clay, sand, and Loess, fronts the 
cliffs. Under it are traces of a raised beach in the form of rolled and water-worn 
pebbles, but there is no clear section, nor could I find any fossils. Between Granville 
and St. Paire, is a section showing a small quantity of Rubble-drift on a slope, and 
under it the broken edges of the rock are bent back in a manner similar to the case I 
have recorded in Devonshire. 
The Channel Islands afford evidence of submergence and upheaval of a character 
different from that we have hitherto noticed, but no less striking. Both Guernsey 
* Lambaedie estimated the loss on the Normandy coast at 1 “ pied de roi ” annually. M. Baude men¬ 
tions later observations continued from 1800 to 1847, which show that at the Cape d’Ailly, near Dieppe, 
the loss was 0'80 metre yearly, but at the Cape La Heve, near Havre, it was only 0'30 metre. 
