386 



PHYSICAL GEOGRAPHY. 



CHAPTER XL 



ALTERATIONS OF COAST LINE. 



STRUGGLE for the mastery is perpetually going 

 on between the sea and the dry land, in the 

 course of which extensive changes are effected 

 in the disposition of the coast, though mutual 

 losses in the struggle are compensated by cor- 

 responding gains, so as to leave each of the 

 contending agents in possession of about the 

 same amount of territory. In some places the 

 ocean obtains the superiority by very gradual 

 advances, which only become sensible after 

 long intervals of time, but occasionally, under 

 the action of extraordinary storms, it bounds 

 over the embankments of a low shore, sweeps 

 them away entirely, overflows interior levels, 

 and retains a permanent hold of its conquest. 

 In other places its waters retire before the slow 

 advance of the land, large tracts of which are 

 formed by the constant accumulation of sand 

 or the alluvium of rivers, and the coast in- 

 vades the dominion of the deep, so that where 

 its waves have gently played or wildly raged, 

 a new theatre is created for human industry 

 wwtby Abbey. and the purposes of vegetation. The instances 



in which the sea encroaches in a sudden and violent manner are of rare occurrence ; but 

 taking a view of physical operations through several centuries, we find no inconsiderable 

 number of examples of these hasty and terrible inroads. It has frequently happened in 

 earthquakes, that the sea has rushed upon the shores in tremendous waves, dashed away 

 whole masses of coast, and accomplished a lodgement for its floods where fields were ver- 

 dant, and man had long enjoyed a quiet habitation. During the great earthquake at 

 Lisbon, the water retired from the harbour and left the bar dry, but it suddenly rolled in 

 again in an immense volume, which rose in some places to the height of sixty feet, inun- 

 dating the western shores of Portugal, and a sea-port called St. EubaFs, about twenty 

 miles south of the Tagus, was engulfed, and totally disappeared. The earthquake which 

 desolated Peru in 1 746 was attended with a similar attack upon the land by the ocean. 

 The Pacific broke with resistless fury upon the coast, destroying several sea- ports, 

 carrying ships a considerable distance up the country, and converting a large tract of 

 inhabited land in the neighbourhood of Callao into a permanent bay. A remarkable 

 swell of the sea occurred at Jamaica in 1780, the effect of submarine disturbance, when a 

 great wave assailed the western coast, and swept away the whole town of Savanna la 

 Mar in an instant, so that not a vestige of man, beast, or habitation survived the irrup- 

 tion. But in 1692 the coast of the island suffered still more extensive ravages from the 

 violence of an earthquake. At Port Royal, then the capital, three quarters of the build- 

 ings, and the ground they stood upon, sunk down with their inhabitants entirely under 



