Neither Darwin nor Wallace were the first to propose evolution by natural selection. Both acknowledged that
Patrick Matthew was first.
http://darwin-online.org.uk/content/frameset?pageseq=1&itemID=F1705&viewtype=text
Gardeners' Chronicle and Agricultural Gazette no. 16 (21 April [, 1860]): 362-363.
...
I have been much interested by Mr. Patrick Matthew's communication in the Number of your Paper, dated April 7th. I freely acknowledge that Mr. Matthew has anticipated by many years the explanation which I have offered of the origin of species, under the name of natural selection. I think that no one will feel surprised that neither I, nor apparently any other naturalist, had heard of Mr. Matthew's views, considering how briefly they are given, and that they appeared in the appendix to a work on Naval Timber and Arboriculture. I can do no more than offer my apologies to Mr. Matthew for my entire ignorance of his publication. If another edition of my work is called for, I will insert a notice to the foregoing effect.
- Charles Darwin, Down, Bromley, Kent.1
http://www.nhm.ac.uk/research-curat...llace-letters-online/1586/1365/T/details.html
...
To my mind your quotations from Mr. Patrick Matthew are the most remarkable things in your whole book, because he appears to have completely anticipated the main ideas both of the "Origin of Species" & of "Life & Habitat".
...
Believe me
Yours very faithfully
Alfred R. Wallace