Il6 GEOLOGY [CHAP. IX 



Letter 480 contented with my small volume, 1 which, small as it is, cost 

 me much time. The pleasure of observation amply repays 

 itself: not so that of composition ; and it requires the hope of 

 some small degree of utility in the end to make up for the 

 drudgery of altering bad English into sometimes a little better 

 and sometimes worse. With respect to craters of elevation, 2 

 I had no sooner printed off the few pages on that subject 

 than I wished the whole erased. I utterly disbelieve in 

 Von Buch and de Beaumont's views ; but on the other hand, 

 in the case of the Mauritius and St. Jago, I cannot, perhaps 

 unphilosophically, persuade myself that they are merely 

 the basal fragments of ordinary volcanoes ; and therefore I 

 thought I would suggest the notion of a slow circumferential 

 elevation, the central part being left unelevated, owing to the 

 force from below being spent and [relieved?] in eruptions. On 

 this view, I do not consider these so-called craters of elevation 

 as formed by the ejection of ashes, lava, etc., etc., but by a 

 peculiar kind of elevation acting round and modified by 

 a volcanic orifice. I wish I had left it all out ; I trust that 

 there are in other parts of the volume more facts and less 

 theory. The more I reflect on volcanoes, the more I appre- 

 ciate the importance of E. de Beaumont's measurements 3 

 (even if one does not believe them implicitly) of the natural 

 inclination of lava-streams, and even more the importance of 

 his view of the dikes, or unfilled fissures, in every volcanic 

 mountain, being the proofs and measures of the stretching 

 and consequent elevation which all such mountains must have 

 undergone. I believe he thus unintentionally explains most 

 of his cases of lava-streams being inclined at a greater angle 

 than that at which they could have flowed. 



But excuse this lengthy note, and once more let me thank 

 you for the pleasure and encouragement you have given me- 



1 Geological Observations on the Volcanic Islands visited during the 

 Voyage of H. M.S. Beagle-. London, 1844. A French translation has 

 been made by Professor Renard of Ghent, and published by Reinwald 

 of Paris in 1902. 



2 Geological Observations, pp. 93-6. 



3 Elie de Beaumont's views are discussed by Sir Charles Lyell both 

 in the Principles of Geology (Ed. X., 1867, Vol. I. pp. 633 et seq.) 

 and in the Elements of Geology (Ed. III., 1878, pp. 495, 496). See 

 also Darwin's Geological Observations, Ed. II., 1876, p. 107. 



