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 ' ; irt 

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

 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.| 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 J 

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



* Thomas Davidson, F.R.S., win to R. Chambers (April 30, 



born in Edinburgh, May 17, 1817 ; 1861). 



died 1885. His researches were t John William Salter; b. 1820, 



chiefly connected with the sciences d. 1869. He entered the service of 



of geology and palaeontology, and the Geological Survey in 1846, and 



were directed especially to the ultimately became its Palaeonto- 



elucidation of the characters, classi- logist, on the retirement of Edward 



fication, history, geological and Forbes, and gave up the office 



geographical distribution of recent in 1863. He was associated with 



and fossil Brachiopoda. On this several well-known naturalists in 



subject he brought out an important their work with Sedgwick, Mur- 



work, ' British Fossil Brachiopoda,' chison, Lyell, Ramsay, and Huxley. 



5 vols. 4to. (Cooper, 'Men of the There are sixty entries under his 



Time,' 1884.) name in the Royal Society Cata- 



f " Mr. Davidson is not at all a logue. The above facts are taken 



full believer in great changes of from an obituary notice of Mr. 



species, which will make his work Salter in the ' Geological Maga- 



all the more valuable." C. Dar- zine,' 1869. 



