[page] 581

May I add a sentence from a private letter of Mr. Darwin's, which helps out the same view on a larger scale? "The contrast," he says, "in the colour of the birds in Patagonia" (where he had just noticed "the sombre aspect of nature"), "and on the bright green flower-decked plains of La Plata is very striking."¹

¹ Darwin to [Grant Allen] [before 21 February 1879] Correspondence vol. 27. In the original letter Darwin referred to "the sombre aspect of nature" in the Galapagos and Patagonia.