Mr.
Swaysland, of Brighton, who during the last forty years has paid close attention to our migratory birds, informs me that he has often shot wagtails (Motacillae), wheatears, and whinchats (Saxicolae), on their first arrival on our shores, before they had alighted; and he has several times noticed little cakes of earth attached to their feet.

Many facts could be given showing how generally soil is charged with seeds.
For instance, Professor Newton sent me the leg of a red-legged partridge (Caccabis rufa) which had been wounded and could not fly, with a ball of hard earth adhering to it, and weighing six and a half ounces.

The earth had been kept for three years, but when broken, watered and placed under a bell glass, no less than eighty-two plants sprung from it: these consisted of twelve monocotyledons, including the common oat, and at least one kind of grass, and of seventy dicotyledons, which consisted, judging from the young leaves, of at least three distinct species.
With such facts before us, can we doubt that the many birds which are annually blown by gales across great spaces of ocean, and which annually migrate--for instance, the millions of quails across the Mediterranean--must occasionally transport a few seeds embedded in dirt adhering to their feet or beaks?
But I shall have to recur to this subject.
As icebergs are known to be sometimes loaded with earth and stones, and have even carried brushwood, bones, and the nest of a land-bird, it can hardly be doubted that they must occasionally, as suggested by Lyell, have transported seeds from one part to another of the arctic and antarctic regions; and during the Glacial period from one part of the now temperate regions to another.

In the Azores, from the large number of plants common to Europe, in comparison with the species on the other islands of the Atlantic, which stand nearer to the mainland, and (as remarked by Mr.H.C.

Watson) from their somewhat northern character, in comparison with the latitude, I suspected that these islands had been partly stocked by ice-borne seeds during the Glacial epoch.