366 



SPREAD OF EVOLUTION. 



[l86l. 



C. Darwin to Thomas Davidson* 



Down, April 26, 1861. 



My DEAR Sir, I hope that you will excuse me for ven- 

 turing to make a suggestion to you which I am perfectly well 

 aware it is a very remote chance that you would adopt I do 

 not know whether you have read my ' Origin of Species ' ; in 

 that book I have made the remark, which I apprehend will 

 be universally admitted, that" as a whole, the fauna of any 

 formation is intermediate in character between that of the 

 formations above and below. But several really good judges 

 have remarked to me how desirable it would be that this 

 should be exemplified and worked out in some detail 

 and with some single group of beings. Now every one will 

 admit that no one in the world could do this better than you 

 with Brachiopods. The result might turn out very unfavour- 

 able to the views which I hold ; if so, so much the better for 

 those who are opposed to me.f But I am inclined to suspect 

 that on the whole it would be favourable to the notion of 

 descent with modification ; for about a year ago, Mr. Salter % 

 in the museum in Jermyn Street, glued on a board some 



* Thomas Davidson, F.R.S., 

 born in Edinburgh, May 17, 18 17 ; 

 died 1885. His researches were 

 chiefly connected with the sciences 

 of geology and palaeontology, and 

 were directed especially to the 

 elucidation of the characters, classi- 

 fication, history, geological and 

 geographical distribution of recent 

 and fossil Brachiopoda. On this 

 subject he brought out an important 

 work, ' British Fossil Brachiopoda,' 

 5 vols. 4to. (Cooper, ' Men of the 

 Time,' 1884.) 



f " Mr. Davidson is not at all a 

 full believer in great changes of 

 species, which will make his work 

 all the more valuable." C. Dar- 



win to R. Chambers (April 30, 

 1861). 



% John William Salter; b. 1820, 

 d. 1869. He entered the service of 

 the Geological Survey in 1846, and 

 ultimately became its Palaeonto- 

 logist, on the retirement of Edward 

 Forbes, and gave up the office 

 in 1863. He was associated with 

 several well-known naturalists in 

 their work with Sedgwick, Mur- 

 chison, Lyell, Ramsay, and Huxley. 

 There are sixty entries under his 

 name in the Royal Society Cata- 

 logue. The above facts are taken 

 from an obituary notice of Mr. 

 Salter in the ' Geological Maga- 

 zine,' 1S69. 



