448 GEOGRAPHICAL DISTRIBUTION [Chap. VI 



Letter 341 S.E. and S.W. Australia : I suspected after my letter was 

 gone that the case must be as it is. You know of course that 

 nearly the same rule holds with birds and mammals. Several 

 years ago I reviewed in the Annals of Natural History 1 

 Waterhouse's Mammalia, and speculated that these two 

 corners, now separated by gulf and low land, must have 

 existed as two large islands ; but it is odd that productions 

 have not become more mingled ; but it accords with, I think, 

 a very general rule in the spreading of organic beings. I 

 agree with what you say about Lyell ; he learns more by 

 word of mouth than by reading. 



Henslow has just gone, and has left me in a fit of enthu- 

 siastic admiration of his character. He is a really noble and 

 good man. 



Letter 342 To G. Bentham. 2 



Down, Dec. 1st [1858?]. 

 I thank you for so kindly taking the trouble of writing 

 to me, on naturalised plants. I did not know of, or had 



1 Annuls and Mag. of Nat. Hist., Vol. XIX., 1847, pp. 53-56, an 

 unsigned review of A Natural History of the Mammalia, by G. R. 

 Waterhouse, Vol. I. The passage referred to is at p. 55 : "The fact of 

 South Australia possessing only few peculiar species, it having been 

 apparently colonised from the eastern and western coasts, is very interest- 

 ing ; for we believe that Mr. Robert Brown has shown that nearly the 

 same remark is applicable to the plants ; and Mr. Gould finds that most 

 of the birds from these opposite shores, though closely allied, are distinct. 

 Considering these facts, together with the presence in South Australia 

 of upraised modern Tertiary deposits and of extinct volcanoes, it seems 

 probable that the eastern and western shores once formed two islands, 

 separated from each other by a shallow sea, with their inhabitants 

 generically, though not specifically, related, exactly as are those of New 

 Guinea and Northern Australia, and that within a geologically recent 

 period a series of upheavals converted the intermediate sea into those 

 desert plains which are now known to stretch from the southern coast far 

 northward, and which then became colonised from the regions to the east 

 and west." On this point see Hooker's Introductory Essay to the Flora 

 of Tasmania, p. ci, where Jukes' views are discussed. For an interesting 

 account of the bearings of the submergence of parts of Australia, see 

 Thiselton-Dyer, R. Geogr. Soc. four., XXII., No. 6. 



3 George Bentham (1800-83), son of Sir Samuel Bentham, and 

 nephew of Jeremy, the celebrated authority on jurisprudence. Sir 

 Samuel Bentham was at first in the Russian service, and afterwards in 

 that of his own country, where he attained the rank of Inspector-General 



