CHAP. XIII. CONTINENTAL ICE OF GREENLAND. 279

1834, ascertained in 1830-32, in company with CaptainGraah, that the whole coast from lat. 60° to about 70° northhas been subsiding for the last four centuries, so that someancient piles driven into the beach to support the boats ofthe settlers have been gradually submerged, and woodenbuildings have had to be repeatedly shifted farther inland.*

In Norway and Sweden , instead of such a movement ofsubsidence, the land is slowly rising; but we have only tosuppose that formerly, when it was covered like Greenland with continental ice, it sank at the rate of several inches orfeet in a century, and we shall be able to explain why marinedeposits are found above the level of the sea, and why thesegenerally overlie polished and striated surfaces of rock.

We know that Greenland was not always covered withsnow and ice, for when we examine the tertiary strata ofDisco Island (of the upper miocene period) we discover therea multitude of fossil plants, which demonstrate that, likemany other parts of the arctic regions, it formerly enjoyed amild and genial climate. Among the fossils brought fromthat island, lat. 70° N., Professor Heer has recognisedSequoia Langsdorfii, a coniferous species which flourishedthroughout a great part of Europe in the miocene period,and is very closely allied to the living Sequoia sem/pervirensof California . The same plant was found fossil by Sir John Richardson within the arctic circle, far to the west onthe Mackenzie River , near the entrance of Bear River ; alsoby some Danish naturalists in Iceland to the east. The Ice­ landic surturbrand, or lignite, of this age has also yielded arich 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 mioceneplants of Europe . Thirteen of the number are arborescent;and amongst others is a tulip-tree ( Linodendron ), with its

Principles of Geology, 11th ed. eh. xxxi. p. 196.