669 



agency of lloaling ice 1 ; seaweeds on which Ihe molluscs are fixed; 

 currents along the sea bottom; the waves on precipitous coasts; 

 seabirds; fishes and olher animals; (2) the existence of a previous, 

 higher temperature in Ihe Arctic Sea which doubtless made il pos- 



sil)lc for the species lo live at greater depths llien I han now. 



Whether a warmer post-glacial epoch did occur in the Færoes 

 has hardly heen proved. The faet that some of the flowering 

 piants of the Færoes do not bear fruit (see Ostenfeld, p. 106 

 where, e. g. Vaccinium Vitis idæa may probably also have heen 

 mentioned) may be referred to liere. But this phenomenon, the 

 correctness of which is by no means satisfactorily demonstrated, 

 mav be explained wilhout a hypothesis of the piants having im- 

 migrated during a warmer post-glacial epoch 2 . Geikie in »Pre- 

 historic Europe« (pp. 514, 518 and 519) mentions that in post-glacial 

 times a warmer climate prevailed, which permitted the growth of 

 trees on the Færoes, and he further mentions that in the peat of 

 the Færoes, birch wood as thick as an arm has been met with; 

 but according to my knowledge, no other trees have been found 

 in the bogs but juniper {Juniperus communis), and their remains 

 do not appear to be of any unusual size. 



But, on the other hånd, it is probahle that the Færoes also 

 have had a warmer post-glacial epoch, since there is evidence of a 

 warmer post- glacial climate in Scandinavia; and Johansen (1. c. 

 p. 402) also mentions a warmer period. 



In regard to the agencies mentioned by Johansen and quoted 

 above by means of which littoral shells are transported, I am of 

 opinion that ocean currents must play the most prominent part, 

 in faet they must be of importance everywhere. As for the ridge 

 between the Shetlands and Greenland a strong submarine current 

 must unquestionably flow over it which would perhaps convey the 

 light shells to great depths. 



Another very weighty objection has also quite recently been 

 brought foward against the hypothesis of a great land depression, 

 viz. by the Danish geologist Boggild 3 . He points out, e. g. that 



1 Several writers have giveD decided instances of the transport of mussel 

 shells, etc. by the agency of ice, e. g. Bay (Meddelelser om Grønland, XIX ; 

 H. Reusch (Naturen. 1900 and 1902); Hans Kiær (Naturen, 1902). See also 

 Wa nu in g: >Om Grønlands Vegetations Meddel, om Grønland, XII, 18.S7. pp. 211 — 13. 



2 See Warming: Om Gronlands Vegetation, I. c. p. 20.'J. 



3 O. B. Boggild: Om en formotiet Sænkning af Havbunden mellem Island og 

 Jan Mayen. Videnskabelige Meddelelser 1902. 



