18431882] GLACIAL PERIOD 461 



fit to travel home I know not. I most sincerely hope that Letter 350 

 Mrs. Huxley keeps up pretty well. The work which most 

 men have to do is a blessing to them in such cases as 

 yours. God bless you. 



Sir H. Holland came here to see her, and was wonder- 

 fully kind. 



To C. Lyell. Letter 351 



Down, Nov. 2Oth [1860]. 



I quite agree in admiration of Forbes' Essay, 1 yet, on 

 my life, I think it has done, in some respects, as much 

 mischief as good. Those who believe in vast continental 

 extensions will never investigate means of distribution. 

 Good heavens, look at Heer's map of Atlantis ! I thought 

 his division and lines of travel of the British plants very 

 wild, and with hardly any foundation. I quite agree with 

 what you say of almost certainty of Glacial epoch having 

 destroyed the Spanish saxifrages, etc., in Ireland. 2 I 

 remember well discussing this with Hooker ; and I suggested 

 that a slightly different or more equable and humid climate 

 might have allowed (with perhaps some extension of land) 

 the plants in question to have grown along the entire 

 western shores between Spain and Ireland, and that subse- 

 quently they became extinct, except at the present points 

 under an oceanic climate. The point of Devonshire now 

 has a touch of the same character. 



I demur in this particular case to Forbes' transportal 

 by ice. The subject has rather gone out of my mind, and 

 it is not worth looking to my MS. discussion on migration 

 during the Glacial period ; but I remember that the distri- 

 bution of mammalia, and the very regular relation of the 

 Alpine plants to points due north (alluded to in Origin), 

 seemed to indicate continuous land at close of Glacial period. 



To J. D. Hooker. Letter 352 



Down, March i8th [1861]. 



I have been recalling my thoughts on the question 

 whether the Glacial period affected the whole world con- 

 temporaneously, or only one longitudinal belt after another. 



1 Memoir of the Geolog. Survey of the United Kingdom , Vol. I., 1846. 



2 See Letter 20. 



