ScnARFF — Former Land-Br'ul(ic hetween N. Europe and N. America. 23 



plants and animals common to tiie two continents were so largely confined 

 to the coastal districts. Bnt from what has hecn mentioned we have no 

 reason to infer that American birds do habitually alight on the west coast of 

 Ireland on first reaching Europe. It seems highly probable that they cross by 

 way of Greenland. We should therefore expect all the species of the 

 invertebrates and plants common to the two continents to be found in 

 Greenland as well. This is not so. Only comparatively few of them are met 

 with in Greenland. The theory that the resemblance in the fauna and flora 

 of eastern North America and western Europe is due to the action of birds 

 is, I think, not supported by suflficient evidence. 



The third theory, that the identical species on either side of the Atlantic 

 Ocean are the result of a direct land-connexion between Scotland, Iceland, 

 Greenland, and Labrador, such as I have suggested in the illustration 

 (fig. 1), appears to me to be well founded on geological, bathymetrical, 

 and biological evidence. No decisive testimony, however, has as yet been 

 brought forward to show during what geological period this land-bridge 

 was formed and how long it lasted. The assumption that such geographical 

 conditions prevailed during early Tertiary times is very widespread. That 

 this state continued during the Miocene period is likewise maintained by 

 many ; though Professor Dawkins and a few others do not admit the existence 

 of the northern land-bridge in Pliocene or more recent times.' Sir Archibald 

 Geikie's researches point to the production of the great basalt plateaux of 

 north-western Europe in early Tertiary times. These plateaux formed a 

 continuous tract of land, as far as the Faroes at any rate. He proves that 

 in many places, such as Iceland, the Faroes, and the West of Scotland, 

 enormous subsidence subsequently took place. Yet he gives us no idea of 

 the approximate geological date of that event.- 



Once we admit that animals and plants were able to survive the Glacial 

 period in northern latitudes, a land-connexion such as suggested in Pliocene 

 times would readily account for the presence of all the animals and plants 

 common to Europe and America. By many of those best able to judge, an 

 admission to that effect has been made. Pliocene deposits are scanty in the 

 British Islands; yet they yield valuable suggestions as to the geographical con- 

 ditions of the North Atlantic. An examination of the fossil invertebrates 

 contained in the St. Erth beds in Cornwall, which are of Pliocene age, showed 

 that the fauna possessed a remarkably southern facies, and that there was a 

 total absence of boreal or arctic species. This fact led Professor Kendall and 



' Dawkins, W. Boyd, " Early Man in Britain," p. 43. 



' Geikie, A., " Basalt Plateaux of North-'Westem Europe," p. 403. 



