PHYSICAL CONDITIONS—POSTGLACIAL. 519 



accession of the cold of that period this flora was driven south- 

 ward, and was affected differently in different longitudes. In 

 Greenland many species were exterminated, being, as it were, 

 driven into the sea at the southern extremity of the peninsula, 

 where only the hardiest survived. On the return of warmth 

 the Greenland survivors migrated northward, peopling the 

 peninsula with the hardiest of the species of its former flora, 

 unmixed with American species, and unchanged in aspect, from 

 never having been brought into competition with those of any 

 other flora." 1 



From what I have said as to the conditions that obtained 

 in North-west Europe during the latest glacial epoch, it is 

 hardly possible that the flora of Greenland can date back to so 

 early a period as Sir Joseph supposes. That of the Fasroe 

 Islands is certainly of postglacial origin, for the ice of the last 

 cold period completely enveloped the whole group, and must 

 have destroyed every vestige of their vegetation. I have not 

 visited Iceland, but it is well known that the marks of glaciation 

 are conspicuous there, not only in the interior, but upon the 

 lower grounds near the coast. 2 Indeed we may be sure that 

 Iceland could hardly have wanted its enveloping mer de glace at 

 a time when the Scandinavian and Scottish ice-sheet filled up 

 the North Sea, and a thick mantle of ice smothered the Feeroe 

 Islands. But even if Iceland were not entirely buried under 

 an icy covering, yet the climatic conditions of the last glacial 



1 Gardeners' Chronicle, August 1878. See also Trails. Linn. Soc, 1860. 



2 W. Sartorius von Waltershausen appears to have been the first to detect 

 glacial striae in Iceland, during a visit in 1846. He traced groovings and furrows 

 from the sea-level inland up to a height of more than 2000 feet ; they were not 

 confined to the valleys, but appeared likewise on the flat basaltic plateaux. He 

 also mentions the occurrence of erratics of granite, and certain other crystalline 

 rocks, upon the north and north-east coasts of Iceland. As Iceland appears to 

 be composed entirely of volcanic rocks, such as basalt, trachyte, tuff, etc., the 

 probabilities are that the stones and blocks referred to by Waltershausen have 

 come, as he suggests, either from Greenland or Scandinavia. See Nattiurlc. Verh. 

 Eoll. Maatseh. Wettensch., Haarlem, Dl. xxiii. pp. 76, 79. R. Chambers has 

 also noted glacial markings in Iceland (Tracings in Iceland and the Faroe 

 Islands, 1856, p. 49), and references to their occurrence appear in most recent 

 books of travel in the island. 



