160 EARTHQUAKES. 



quakes are phenomena with which all students of geology 

 are familiar. In most cases these displacements have 

 been permanent ; and evidences of many of the move- 

 ments which occurred within the memory of man, remain 

 as witnesses of the terrible convulsions with which they 

 were accompanied. 



Movements on coast lines and level tracts, — At the 

 time of the great earthquake of Concepcion, on February 

 20, 1835, much of the neighbouring coast line was sud- 

 denly elevated four or five feet above sea level. This, how- 

 ever, subsequently sank until it was only two feet. A rocky 

 flat, off the island of Santa Maria, was lifted above high- 

 water mark, and left covered with ' gaping and putrefying 

 mussel-shells, still attached to the bed on which they had 

 lived.' The northern end of the island itself was raised 

 ten feet and the southern extremity eight feet.^ 



By the earthquake of 1839, the island of Lemus, in the 

 Chonos Archipelago, was suddenly elevated eight feet.^ 



Of movements like these, especially along the western 

 shores of South America, Darwin, who paid so much atten- 

 tion to this subject, has given many examples. In 1822, 

 the shore near Valparaiso was suddenly lifted up, and 

 Darwin tells us that he heard it confidently asserted ' that 

 a sentinel on duty, immediately after the shock, saw a part 

 of a fort which previously was not within the line of his 

 vision, and this would indicate that the uplifting was 

 not vertical.'^ That the large areas of land should be 

 shifted permanently in horizontal directions, as well as 

 vertically, we should anticipate from the observations 

 which we are able to make upon large fissures which are 

 caused by earthquakes. 



Another remarkable example of sudden movement in 



' Jour. Ruyal Geo. Soe vol. vi. p. 319. 

 2 Darwin, Geolog. Ohservations, p. 232. » Ihid. p. 245. 



