48 



Nr. 3. C. H. Ostknfei.d; 



sliell strata in llu' Vaigat region ahonl lal. 70 N., conlain- 

 ing shells ol' inussels no longer t'ound so far lo Ihe north 

 as Greenland, llieir present northern limit lying al the 

 (iuir of St. Lawrence. As these shell strata are considered 

 post-glacial, they afTord certain evidence of a warnier post- 

 glacial period, and in the coiirse of such a warm period, 

 several American plant species which cannot now be 

 snj)posed to follow so northerly a route as Ihal via Smith 

 Sound, might have gone that way. They would then have 

 been driven farther south, when the climate became colder. 



But farther to Ihe south again, West (Ireenland musl 

 also have received a considerable contingent of American 

 species, in the niany suh-arctic and boreal species; these 

 must have come across Davis Strait. 



Turning to East Greenland we fhid, in the extreme 

 north, some species (e, g. Dralni Adamsii, D. repens and 

 Kpilohiiii)\ (ircticum, Arenarui })send()fri(jida), which must 

 have come from Spitsbergen and other arctic islands in 

 that neighbourhood ; farther south, we lind a little group 

 of species which must presumably have come from Ice- 

 land to the Angmagsalik area (Alchimilla acutidens, Sednm 

 acre, possibly Hieraciiim nlpiniim). For the rest, it is impos- 

 sible to go further into detail as to the routes followed by 

 the immigrants from the east. — 



As to the manner in which each of the species was 

 transported, this is a difficull (pieslion. The natural means 

 of transport are by the aid of water, wind, and animals. 



First as regards Ihe water, in ils lluid state, it is of 

 no great importance as a means of immigration where 

 Greenland is concerned, as only a small number of sea- 

 shore piants (abt. 15) have been found liere. Only Mer- 

 fensin rnnritima. Polentilla (inserina, Ilonckenijd peploides 



