SOME CHAPTERS OF THE TERTIARY HISTORY OF ICELAND 5 



If we were free to base our estimate of age on this tectonic and erosional 

 history, it seems most Hkely that a Lower PHocene or even Miocene age 

 should be assumed for the topmost plateau group. But the relations to the 

 Upper Pliocene sediments in Tjornes, although not at all very clear, seem to 

 indicate a Late Pliocene age for the plateau group. This would demand on the 



Fig. 2. Localities for fossil plants (dots) and marine fauna (crosses) in Iceland 

 from earlier than Late and Post-glacial times. A few uncertain localities of 

 surtarbrandur on Snaefellsnes and the Northwest Peninsula have been ignored. 

 Hatching indicates the areas in which Pflug's "first type" of Icelandic flora occurs 

 (cf. the text, p. 5). L Brjanslaekur; 2, Skardsstrond ; 3, Litlisandur; 4, Hredavatn; 

 5, Stafholt; 6, Sleggjulaekur; 7, Tjornes; 8, Vopnafjordur; 9, Jokuldalur; 10, 

 Bessastadaa and Hengifoss; 11, Lungufell; 12, Holmatindur; 13, Gerpir; 14 



Hoffell. 



Other hand that peneplanation and valley erosion in Iceland had been extreme- 

 ly rapid, and this is not at all easy to comprehend. Absolute dating of the 

 topmost plateau group is very much to be desired. 



A fossil flora is found at a number of horizons in the plateau (Fig. 2). In 

 the lowest ones, a temperate or warm-teinperate climate is indicated. But 

 with increasing height the flora takes on a cooler character. Pflug (1959) has 

 divided the flora into several types: 



B 



