84 A SUMMER IN GREENLAND 
Disko Island reach their northern limit on Hare 
Island, and these are regarded by Mr Porsild as 
relicts of a time subsequent to the Glacial period 
when the climate was more genial than at present. 
The Alpine Potentilla and the Alpine Veronica are 
two examples of the southern species recorded from 
Hare Island. These southern plants ripen their 
seeds and fruits late in the autumn and are met 
with only in places where they are well covered 
with snow during the winter. 
On the beach were substantial pieces of drift- 
wood, a characteristic feature of many parts of the 
Greenland coast. In former days it was from logs 
of wood washed ashore that the Greenlanders 
obtained the whole of the timber used in the 
construction of their boats and weapons. A micro- 
scopical examination of samples of drift-wood has 
demonstrated that much of it comes from the 
forests of northern Siberia: after the fallen stems 
and branches reach the sea by Siberian rivers they 
are carried many hundred miles by the Polar cur- 
rent down the east coast of Greenland, round Cape 
Farewell and north again through Davis Strait 
and Baffin Bay. Drifted logs are abundant on the 
coasts of Spitsbergen, Bear Island, the small and 
lonely island of Jan Mayen, and other Arctic lands. 
If, as is often possible, the provenance of the wood 
can be ascertained, its distribution furnishes valu- 
able information on the subject of ocean currents!. 
1 An account of the botanical nature and provenance of the 
Greenland drift-wood was published in 1903 by Dr Ingrarson 
in the Transactions of the Royal Swedish Academy (Kozg/. 
Svensk. Vetenskapsakad. Hand. vol. 37). 
