238 MIOCENE FLORA OF ICELAND. chap. xiii. 



and is very closely allied to the living Sequoia sempervirens 

 of California. The same plant has been found fossil by Sir 

 John Eichardson within the arctic circle, far to the west on 

 the Mackenzie River, near the entrance of Bear Eiver, also by 

 some Danish naturalists in Iceland to the east. The Ice- 

 landic surturbrand, or lignite, of this age has also yielded a 

 rich harvest of plants, more than thirty-one of them, accord- 

 ing to Steenstrup and Heer, in a good state of preservation, 

 and no less than fifteen specifically identical with mioeene 

 plants of Europe. Thirteen of the number are arborescent j 

 and amongst others is a tulip-tree {Liriodendron), with its fruit 

 and characteristic leaves, a plane (Platanus), a walnut, and a 

 vine, affording unmistakable evidence of a climate in the 

 parallel of the arctic circle which precludes the supposition 

 of glaciers then existing in the neighborhood, still less any 

 general crust of continental ice, like that of Greenland.* 



As the older pliocene flora of the tertiary strata of Italy, 

 like the shells of the coralline crag, before adverted to, 

 p. 210, indicate a temperature milder than that now prevail- 

 ing in Europe, though not so Avarm as that of the upper 

 mioeene period, it is probable that the accumulation of snow 

 and glaciers on the mountains and valleys of Greenland did 

 not begin till after the commencement of the pliocene period, 

 and ma}' not have reached its maximum until the close of 

 that period. 



^Norway and Sweden appear to have passed through all the 

 successive phases of glaciation which Greenland has experi- 

 enced, and others which that country will one day undergo, if 

 the climate which it formerly enjo3'ed should ever be restored 

 to it. There must have been first a period of separate glaciers 

 in Scandinavia, then a Grecniandic state of continental ice, and 

 thirdly, when that diminished, a second period of enormous 

 separate glaciers filling many a valley now wooded with fir and 



*Heer, Recherches sur la Vegetation du Pays tertiaire, &c., 1861, p. 178. 



