MIGRATION 
of sheep and other food, together with a suitable climate, 
would assist in their rapid increase, and once established, 
the mischief would be beyond the poAver of the inhabitants 
to stop or control. 
Great opportunities are afforded to migratory birds to 
cross the sea. They are enabled to rest on at times large 
floating masses, such as that commonly knoAvn as the 
Gulf weed, which, according to some authors, is equal in 
size to the area of Great Britain, and which not only 
affords them a resting-place, but in many instances sup- 
plies them with food, for these masses swarm with living 
animals of endless kinds, insects, crustaceans, mollusca, 
etc. 
Many years since a dead whale floated on the coast of 
Devonshire ; it was almost white, being thickly covered 
Avith the grey phalaropes ; many hundreds of these beauti- 
ful and rare British birds congregated upon the floating 
carcass, and no doubt fed upon parasites and other 
creatures that infested it, and on portions of fat. These 
birds Avere quite tame, and the boys about Devonport and 
Plymouth killed great numbers of them with sticks ; had 
these birds not met Avith such wanton destroyers they 
might, in all probability, have established themselves on 
our shores, as one or tAVO instances are recorded of their 
being found in this country in the breeding season, 
although their great breeding-ground is, according to Mr. 
Yarrell, in the Arctic regions. Porpoises of various species, 
sea-gulls and other fish-eating birds, and fish-devouring 
fishes, folloAV to our shores the shoals of smaller fry upon 
Avhich they feed, just as the lions and other carnivora 
folloAv, across the land, the herds of antelopes, and thus 
distribute and spread their kind. 
In the second volume of Sir Charles Lyell’s Principles 
of Geology is a chapter upon migration of plants and 
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