154 
rriESlUKNT’lS ADDRESS. 
Scandinavia, G9^-° N. lat. ; and it is now spread overalDOut twenty- 
five degrees of latitude, whilst during the Miocene period it was 
limited to the Arctic zone. . . . That the flora of Grinnell 
Land approaches much more closely to that of Spitsbergen than to 
that of Greenland, is easily intelligible from the greater difference 
of latitude. The plant-bearing locality of Grinnell Land lies much 
nearer to the north-west of Spitsbergen (Ice-fiord and King’s Bay), 
than to Disco, and the opposite peninsula of Koursoak, which 
have furnished the Miocene plants of Greenland. We have 
previously pointed out (Flora Foss. Arctica, vol. ii. p. IG) that the 
Miocene flora of Spitsbergen, as compared with that of Greenland, 
would seem to indicate considerable climatic difference, inasmuch 
as a great number of more southern forms which Greenland 
possesses — such as Gastanea, evergreen Magnolke, Primus, Ilex, 
Mac Clintocliia, and CoccoUtes — are wanting in Spitsbergen. The 
same holds good with regard to Grinnell Land.”’'' 
Thus Heer conclusively shows that the Miocene flora increases 
both in genera and species as avo trace it from the 82° of north 
latitude to that of Switzerland ; or in other Avords, that there is a 
thinning out of genera and sjiecies as Ave approach the North Pole. 
As this decrease of species is alike in the deposits both of Grinnell 
Land and Spitsbergen, situated on opposite sides of the hemisphere, 
it is evident that it cannot be due to any change in the geographical 
position of the Pole, — unless Ave admit the fanciful theory of an 
oscillation of the Pole to suit each case, — but is due to climatal 
conditions Avhich even in the Miocene period asserted themselves 
at the North Pole. Therefore, though the temperature of the 
Polar regions at that time must have been considerably higher than 
noAV, yet the Miocene flora decreased toAvards the Pole in the same 
manner as the flora of to-day ; and it is difficult to escape from the 
conclusion that this points to a gradual refrigeration of the 
North Pole, extending through geologic time, OAving to the secular 
cooling of the earth mass, and the radiation of its heat into stellar 
space. 
We find Miocene plant-bearing beds on an immense scale in the 
* Ileor, Quart. Journ. Geol. Soc., 1878, i>p. 06-70. 
