CHAPTER IX 



GEOLOGY 



I. Vulcanicity and Earth-movements. II. Ice-action. III. The 

 Parallel Roads of Glen Roy. IV. Coral Reefs, Fossil 

 and Recent. V. Cleavage and Foliation. VI. Age of 

 the World. VII. Geological Action of Earthworms. 

 VIII. Miscellaneous. 



I. VULCANICITY AND EARTH-MOVEMENTS, 1840-81. Letter 479 



To David Milne. 1 



12, Upper Gower Street, Thursday [March] 2Oth [1840]. 



I much regret that I am unable to give you any informa- 

 tion of the kind you desire. You must have misunderstood 

 Mr. Lyell concerning the object of my paper. 2 It is an 

 account of the shock of February, 1835, in Chile, which is 

 particularly interesting, as it ties most closely together 

 volcanic eruptions and continental elevations. In that paper 

 I notice a very remarkable coincidence in volcanic eruptions 

 in S. America at very distant places. I have also drawn up 

 some short tables showing, as it appears to me, that there 

 are periods of unusually great volcanic activity affecting large 



1 David Milne- Hume (1805-90) was a country gentleman in Berwick- 

 shire who became interested in geology at an early age. He wrote on 

 the Midlothian Coal-field, the Geology of Roxburghshire, the Parallel 

 Roads of Glen Roy, and compiled the Reports presented by a Committee 

 appointed by the Royal Society of Edinburgh to investigate the observa- 

 tion and registration of boulders in Scotland (Quart. Jonrn. Geol. Soc. y 

 Vol. XL VI I., 1891 ; Proc., p. 59). 



2 " On the Connexion of certain Volcanic Phenomena, and on the 

 Formation of Mountain-chains and the Effects of Continental Elevations." 

 Trans. GeoL Soc., Vol. V., 1840, pp. 601-32 [March 7th, 1838]. 



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