168 KAMBLES OP A NATURALIST. 



the course of two or three minutes. A wave of 

 twelve or fifteen feet in height extends across the 

 entire breadth of the river. This is very soon fol- 

 lowed by two or three similar waves, all of which 

 ascend the stream with a terrific noise, and with such 

 rapidity that they destroy every thing that opposes 

 their passage, uprooting trees and carrying away 

 vast tracts of land. The pororoca extends its in- 

 fluence sometimes as far as 600 miles inland. In 

 the open sea, the ground swell is not the less power- 

 ful where it encounters sharp and perpendicular 

 rocks in its passage. These ground waves have often 

 been known to dart their eddying lines of water 

 to the very top of Lot's Wife ; a rock which is situ- 

 ated in the Archipelago of the Philippines, and which 

 rises to an elevation of more than 360 feet. Colonel 

 Emy asserts that these waves act at a depth of 130 

 yards, and that they will raise above the level of the 

 sea columns of water more than 50 yards in height, 

 of 2,000 or 3,000 cubic yards in bulk, and weighing 

 from 2,000 to 3,000 tons. With such figures as these 

 before us, we can no longer feel surprised at the 

 ravages which these waves have committed at Saint- 

 Jean-de-Luz, and we may now more readily believe 

 in the possibility of blocks of stone which weighed 

 four tons, and formed part of the masonry of the 

 pier, having been uplifted and carried to the top of 

 the dyke. 



It is also in a great measure to this ground swell 

 that we must attribute the relative poverty of the 

 coasts of Guettary, Saint-Jean-de-Luz, and Saint 

 Sebastian in respect to marine animals. These 



