By far the most interesting lessons in questions of ancient climates have been taught by fossil plants found in the high northern latitudes of the Arctic regions.

In 1840 Prof. Steenstrup brought from Iceland a number of Tertiary plants which drew the attention of geologists to the evidence afforded by Arctic fossils of a much warmer climate having obtained in Polar regions. Seeing how important are the results which have been arrived at from a study of these northern plants in matters relating to geological climates, we may briefly sketch the main facts of circumpolar Fossil Botany and see on what data the conclusions as to climate have been based.

The late Prof. Heer has given a complete account of Arctic fossil vegetation.

In 1868 appeared the first volume of the Flora Fossilis Arctica; the seventh and last volume was completed in 1883, the last year of Heer's life.

Heer summed up in a few words the results furnished by the rich store of Greenland plants which formed the subject of his last volume. “Cette riche collection nous a donné une connaissance exacte de la végétation qui, dans différentes périodes, a couvert le Gronland.