56 SEA FISHERIES 



and constantly encroaching upon it, and except in 

 the western portion, where there are a few submerged 

 rocks, the depth is inconsiderable. 



The rocks are beyond all computation. Sometimes, 

 as in Brittany, they are isolated ; sometimes they take 

 the form of a series of steps, as on the west coast of 

 Groix ; sometimes they form long reefs, as at Calvados. 

 The floor of the sea is often crossed by valleys, as 

 to the north of the Gironde (other instances are the 

 Cardinals and the Pilier between Yeu and Belle-He), or 

 pitted with depressions (such as the Devil's Sea facing 

 Etretat, the Rays' Hole to the north-west of the He de 

 Batz, the Pirlon Hole to the north-north-west of the 

 He d'Yeu, &c.). 



The off-shore region is characterised by its level 

 rocky plateaux, strewn with pebbles, rocks, gravels, and 

 heaps of shells ; its irregular sandy plains, often inter- 

 posed between the rocky portions ; and lastly, by its 

 rocky chasms. Here and there we find white and 

 green ooze. The simplest form of rocky plateau is 

 exemplified by the Marzelles, WNW. a quarter W. 

 of the Chassiron light on Olron. It consists of 

 enormous flat rocks lying on the bottom. There are 

 many rocky shoals belonging to this category, such 

 as the Chapelle, 120 miles west of Penmarch, which 

 rises in a steep slope from a depth of 155 fathoms to 

 a depth of 40 fathoms, and the shoal of Rochebonne, 

 of which I shall speak presently. Sandbanks, or shoals 

 of fine sand, are very widely distributed. The Sole 

 banks, which are just at the entrance of the Channel, 

 and on the meridian of Cape Clear in Ireland, measure 

 some i, 800 square miles in area. The Little Sole 

 banks, to the south of the former, have an area of 

 about 530 square miles. Both slope towards the west, 



