3o8 PERMANENT ELEVATION OF LAND. [chap. -xiv. 



jiuthors have attempted to explain this, by supposing that 

 the water retains its level, whilst the land oscillates up- 

 wards ; but surel}^ the water close to the land, even on a 

 rather steep coast, would partake of the motion of the 

 bottom : moreover, as urged by Mr. Lyell, similar move- 

 ments of the sea have occurred at islands far distant from 

 the chief line of disturbance, as was the case with Juan 

 Fernandez during this earthquake, and with Madeira 

 during the famous Lisbon shock. I suspect (but the 

 subject is a very obscure one) that a wave, however pro- 

 duced, first draws the water from the shore on which it is 

 advancing to break : I have observed that this happens 

 with the little waves from the paddles of a steam-boat. It 

 is remarkable that whilst Talcahuano and Callao (near 

 Lima), both situated at the head of large shallow bays, have 

 suffered during every severe earthquake from great v/aves, 

 Valparaiso, seated close to the edge of profoundly deep 

 water, has never been overwhelmed, though so often 

 shaken by the severest shocks. From the great wave not 

 immediately . following the earthquake, but sometimes 

 after the interval of even half an hour, and from distant 

 islands being affected similarly with the coasts near the 

 focus of the disturbance, it appears that the wave first rises 

 in the ofiing ; and as this is of general occurrence, the cause 

 must be general : I suspect we must look to the line, where 

 the less disturbed waters of the deep ocean join the water 

 nearer the coast, which has partaken of the movements of 

 the land, as the place where the great wave is first gener- 

 ated ; it would also , appear that the wave is larger or 

 smaller, according to the extent of shoal water which has 

 been agitated together with the bottom on which it rested. 



The most remarkable effect of this earthquake was the 

 permanent elevation of the land ; it would probably be far 

 more correct to speak of it as the cause. There can be no 

 doubt that the land round the Bay of Concepcion was up- 

 raised two or three feet ; but it deserves notice, that owing 

 to the wave having obliterated the old lines of tidal action 

 on the sloping sandy shores, I could discover no evidence of 

 this fact, except in the united testimony of the inhabitants, 

 that one little rocky shoal, now exposed, was formerly 

 covered with water. At the island of S. Maria (about thirty 

 miles distant) the elevation was greater ; on one part. 

 Captain Fitz Roy found beds of putrid mussel-shells still 



