42 



PERCY OUENSEL 



Fig. 2. The south slope of the high ridge along the western half of Masatierra as seen from 



Portozuelo. Photo C. Skottsberg. 



what resembling a water-spout, was seen ascendino from the sea oft" point Bacalao, 

 which proved to be smoke, but at 7 p.m. volcanic ftames were visible through 

 the smoke, which lasted till 2 a.m. on the 21st. The depth of the water on the 

 spot, where the eruption took place, was from 50 to 80 fathoms; no alteration 

 in the depth was detected after the eruption had subsided" (17, p. 818). Sutcliff'e 

 has published an account of the 'earthquake" in a separate publication (18) and 

 reproduced a sketch of the sub-marine eruption (19, p. 387). 



It is obvious that these narratives must refer to a sub-marine volcanic exj^lo- 

 sion. Charles Darwix also mentions the phenomenon in his 'Geological Observa- 

 tions on the Volcanic Islands' (20, p. 149). Renard gives the position of the 

 explosion as i English mile from the island and remarks "that the close prox- 

 imity of a volcanic centre seems therefore to be implied" (8, p. 176). 



The sub-marine eruption must be taken as conclusive evidence that the 

 immediate neighbourhood of the Juan Fernandez Islands has been the seat of 

 volcanic action within the last 115 years. A point of further interest is that the 

 explosion was simultaneous with violent earthquakes on the Chilean coast, as 

 Darwin already observed (see p. 75). 



Briiggen refers to some further observations of sub-marine eruptions in 

 the vicinity of the Juan Fernandez Islands, recorded by Fr. Goll in his paper 

 'Die Erdbeben Chiles' (Miinchener Geogr. Studien 1904, Xr. 14). The following 

 denotements by GOLL are taken from Briiggen (16, p. 332): 



