1840— iSSiJ EARTH-MOVEMENTS 125 



wish to read them over again ; I have, however, re-lent your Letter 

 work to Mrs. Rich, who, like all whom I have met, has been 

 much interested by it. 1 will stop about my own Geology. 

 But I see I must mention that Scrope did suggest (and I 

 have alluded to him, p. [18, 1 but without distinct reference 

 and I fear not sufficiently, though I utterly forgot what he 

 wrote) the separation of basalt and trachyte ; but he does not 

 appear to have thought about the crystals, which I belii 

 to be the keystone of the phenomenon. 1 cannot but think 

 this separation of the molten elements has played a great 

 part in the metamorphic rocks: how else could the basaltic 

 dykes have come in the great granitic districts such as 

 those of Brazil ? What a wonderful book for labour is 

 d'Archiac ! . . . - 



To Lady Lyell. Letter 484 



Down, Wednesday night [1S49 ?]• 

 I am going to beg a very very great favour of you : it 

 is to translate one page (and the title) of either Danish or 

 Swedish or some such language. I know not to whom else 

 to apply, and I am quite dreadfully interested about the 

 barnacles therein described. Does Lyell know Loven, 3 or 

 his address and title? for I must write to him. If Lyell 

 knows him 1 would use his name as introduction ; Loven I 

 know by name as a first-rate naturalist. 



Accidentally I forgot to give you the Footsteps^ which 1 

 now return, having ordered a copy for myself. 



I sincerely hope the " Craters of 1 denudation " 4 prosper ; I 

 pin my faith to this view. 



1 Geological Observations^ Ed. 11., 1876. Chapter VI. opens with a 

 discussion "On the Separation of the Constituent Minerals of Lava, 

 according to their Specific Gravities." Mr. Darwin calls attention to the 

 fa< t that Mr. P. Scrope had speculated on the subject of the separation 

 of the trachytic and basaltic series of lavas (p. 113). 



3 Possibly this refers to d'Archiac's Histoire des Progris tic hi 



logie, 1848. 



3 S. L. Loven published numerous papers on Cirripedes and other 

 zoological subjects in the Stockholm Ofversigt and elsewhere between 

 1838 and 1882. 



4 " On Craters of Denudation, with Observations on the Structure 

 and Growth oi Volcanic Cones.'' Pr . i Vol. VI., 1S50, 

 pp. 207-34. In a letter to Bunbury (Jan. 17th, 1850) Lyell wrote: 



