The exact age of the basalts and intercalated tuff-beds of Iceland is still uncertain. Palæontological dating relies almost solely on plant fossils the occurrence of which is known from many different localities in western Iceland. No plant fossils have hitherto been found in eastern Iceland. In summer 1952 an expedition set out from Scotland to search for plant fossils and lignite deposits intercalated in the East Icelandic Volcanic Series. Such deposits were found on the northern flank of the mountain Tungufell.

Macroscopical remains of plants were rare and badly preserved as compared with the finds in western Iceland, but a microscopical investigation of the lignite yielded 22 types of pollen and spores and 19 species and varieties of diatoms. The flora differs from that known of western Iceland; macroscopical remains and pollen of Abietineæ are abundant in western Icelandic sediments but are entirely absent in the Tungufell flora. The Tungufell flora appears to be younger than the fossil flora of western Iceland; however, the possibility that the difference between the Tungufell flora in East Iceland and the flora found in West Icelandic deposits is due to different ecological factors cannot be excluded. Many further investigations are required before this question may be satisfactorily answered.