18401881] EARTjH-MOVEMENTS 137 



mountain chains are mere accidents resulting from the eleva- Letter 489 

 tion of an area, and as mountain chains are generally long, 

 so should I view areas of elevation as generally large. 



Your old original view that great oceans must be sinking 

 areas, from there being causes making land and yet there 

 being little land, has always struck me till lately as very 

 good. But in some degree this starts from the assumption 

 that within periods of which we know anything there was 

 either a continent in such areas, or at least a sea-bottom of 

 not extreme depth. 



To C. Lyell. Letter 490 



King's Head Hotel, Sandown, Isle of Wight, July i8th [1858]. 



I write merely to thank you for the abstract of the Etna 

 paper. 1 It seems to me a very grand contribution to our 

 volcanic knowledge. Certainly I never expected to see 

 E. de B.'s [Elie de Beaumont] theory of slopes so completely 

 upset. He must have picked out favourable cases for 

 measurement. And such an array of facts he gives ! You 

 have scotched, and will see die, I now think, the Crater of 

 Elevation theory. But what vitality there is in a plausible 

 theory ! 2 



To C. Lyell. Letter 491 



Down, Nov. 25th [1860]. 



I have endeavoured to think over your discussion, but not 

 with much success. You will have to lay down, I think, 

 very clearly, what foundation you argue from four parts 

 (which seems to me exceedingly moderate on your part) of 



of the same Power by which Continents are Elevated," Trans. Geol. Soc. y 

 Vol. V., p. 601, 1840. "Bearing in mind Mr. Hopkins' demonstration, 

 if there be considerable elevation there must be fissures, and, if fissures, 

 almost certainly unequal upheaval, or subsequent sinking down, the 

 argument may be finally thus put : mountain chains are the effects of 

 continental elevations ; continental elevations and the eruptive force 

 of volcanoes are due to one great motive power, now in progressive 

 action . . . " (Joe. cit., p. 629). 



1 " On the Structure of Lavas which have Consolidated on Steep 

 Slopes, with Remarks on the Mode of Origin of Mount Etna and on the 

 Theory of ' Craters of Elevation,' " by C. Lyell, Phil. Trans. R. Soc., 

 Vol. CXLVIII., p. 703, 1859. 



* The rest of this letter is published in Life and Letters, II., p. 129. 



