374 



and after the convulsion. Among others, Osorno, of which the 

 cone rises 3900 feet above the sea, and which is situated on the 

 mainland north-east of the island of Chiloe was in eruption, lava 

 being seen to flow from its crater. Several others are also noticed, 

 and the lava emitted from one of them is stated to have covered 

 an area eight leagues in circumference and to the depth of 3^ yards. 

 The ashes reached to the distance of 300 leagues. I refer you to 

 these statements because it is rare to meet with any recent descrip- 

 tions of the emission of lava and ashes from the high cones of the 

 Andes. 



The same writer was informed that the strata of clay-slate, form- 

 ing the shore of the Bay of Conception, were elevated from three to 

 four feet, whereas the rise at San Vicente, south of Talcahuano, 

 amounted to only 1^ feet. Mr. Caldcleugh was also informed that 

 the island of Santa Maria, in the Bay of Conception, was upheaved 

 about eight feet. 



At the same time the island of Juan Fernandez, distant 360 miles 

 from Chili, was violently shaken and devastated by a great wave. 

 A dense column of vapour issued from the sea about a mile from 

 the coast, and flames were seen at the same spot in the night which 

 illumined the whole island. At this point in the sea whence the 

 flames were emitted the depth of water was afterwards ascertained 

 to be no less than 69 fathoms. 



At a court-martial, lately held at Portsmouth, in consequence of 

 the wreck of the Challenger frigate on the coast of Chili, in May 

 1835, some notes of Capt. FitzRoy were read, and afterwards com- 

 municated by Capt. Beaufort to the Society, in which he describes 

 some remarkable alterations produced by the earthquake of February 

 in the direction of the currents on the Chilian coast. A more de- 

 tailed account of the convulsion has just been received at the Ad- 

 miralty from the same officer, with a sight of which I have been 

 favoured, but no allusion is here made to the currents. There are, 

 however, other facts perfectly new and of the highest importance at- 

 tested in this memoir, and as they come from an observer of great 

 experience in hydrographical surveying, who examined the Bay of 

 Conception immediately after the shocks, they will remove all doubts 

 from the minds of those who have questioned the power of earth- 

 quakes to cause the permanent upheaval of land. 



Capt. FitzRoy states, that on the 20th of February, 1835, the 

 earthquake was felt at all places between Copiapo and Chiloe from 

 north to south, and from Mendoza to Juan Fernandez from east 

 to west. Conception and other towns were thrown down. After 

 the shock the sea retired ; the vessels in the bay grounded, even 

 those which had been lying in seven fathoms water ; all the shoals 

 in the bay were visible ; and soon afterwards a wave rushed in and 

 then retreated, and was follovved by two other waves. The verti- 

 cal height of these waves does not appear to have been greater 

 than from 16 to 20 feet, although they rose to much greater heights 

 when they rushed upon a sloping beach. During the shocks the 

 earth opened and closed rapidly in numerous places. The direction 



