163 THE OCEAN. r 



first strike the two capes placed as guardians at the two extremities 

 of the bay ; here they break their force, and are thrown back 

 against the tranquil waters of the bay. Thus arrested in their 

 speed, they deposit tlie earthy matters which they hold in suspension, 

 and also the heavier fragments torn from the neighbouring promon- 

 tories. At the entrance to the fjords of Scandinavia, of Terra del 

 Fuego, and all the other moimtainoiis countries with deeply indented 

 shores, the clear and deep water of the open sea only brings with it 

 a relatively small quantity of debris, and can only form a submarine 

 bank * from point to point. But along the lower coasts where the 

 tide drives before it masses of sand and clay, the ramparts of alluvium 

 constructed by the waves emerge gradually from the bosom of the 

 waters. 



Under the alternate influence of the ebb and flow, the sand and 

 shingle are gradually deposited against the rocks of the capes, and thus 

 the}' form at the entrance of the ba)'' true jetties, the free extremities 

 of which advance to meet each other. Being elongated unceasingly, 

 the two segments end by uniting midway between the two capes, and 

 thus form a large arc of a circle, the convexity of which is turned 

 towards the ancient shore. The most furious assaults of the sea only 

 serve to consolidate these banks by bringing other materials to them, 

 and raising them above the level of the tides. 



All these sea-banks present a geometrical regularity in their section ; 

 their form is, so to say, the visible expression of the laws which 

 govern the undulation of the waves. Most often that part which 

 fronts the sea is composed of several separate slopes which correspond 

 to the different levels of low water, high tide, and storms : but all 

 these beaches present uniformly a graceful curve, modelled by the 

 breakers. At the base of the embankment the slope is very slight, 

 and simply continues the declivity from the bottom of the sea : but 

 it rises suddenly at an angle that is sometimes not less than from 30 

 to 35 degrees. Immediately beyond this edge a counter-slope begins 

 where the upper curve of every high wave spreads in a foaming sheet. 

 Further on rises a second talus, which the stormy waves sometimes 

 strike and consolidate. The inclination of this second stasre which 

 looks towards the sea is very slight. From this side^ the materials 

 of the embankment, sheltered from the force of the wind, and from 

 the violence of the waves, are gradually heaped up, and may even at 

 length be covered by a bed of vegetable earth. Above this level 

 dunes rise, or else we find the surface of the ancient bay transformed 

 * Danvin, South America, p. 24. 



