^0 CARL SKOTTSBERG, A BÖTANICAL SURVEY OF THE FALKLAND ISLANDS. 



factory conclusion as to tbe highest marine level. The highest terraces recorded 

 (NoRDENSKJÖLD 50 — 60 111,, Halle 100—110 m.) have not been proved to have been 

 formed by tlie sea. 



Our knowledge after Darwin of tlie tertiary flora is mainly derived from investi- 

 gations carried out duriiig tbe Swedish Expedition to the Magellan territories in 1895 — 97 

 by NoRDENSKJÖLD aiid Dusen. The material was worked up by the latter (26). 

 Nothing has yet been published of the observations and collections made during 

 our voyage. One of the richest localities, the valley of Rio de las Minas near Sandy 

 Point was miniitely surveyed by Dr, Halle, wliose discoveries will, I think, add 

 considerably to our knowledge of the tertiary flora. 



According to Darwin's and Dusén's accounts it appears that the land was cove- 

 red by forests, which, however, were not confined to the present area occupied by ar- 

 boreous vegetation, but also extended eastward över the present steppe region. The 

 climate must have been considerably more humid than now; probably it was not uni- 

 form all över the coimtry, but more Continental towards the east. The flora seems to 

 have borne the same general stamp as now ; the forest trees belonged to the genus Notho- 

 fagus, which was more rich in species than now. Most of the species found were deci- 

 duous, but there occur, here and there, leaves of two evergreen beeches in the same 

 strata, and it is probable that such beeches composed the forests in the western and 

 Southern parts just as they do now. Their occurrence with deciduous beeches further 

 east is not surprising, for even now single trees of the evergreen N. hetuloides are 

 found in the forests of N. piimilio. Some of the fossil species are nearly related to 

 living ones ; Dusen is inclined to regard them as their ancestors. 



There are sufficient proofs that the tertiary climate was Avarmer than at present; 

 this is indicated by certain types of Nothofagus, related to or even identical with 

 N. ohliqua, and by Araucaria Nathorstii, discovered by Dusen in the Minas deposits 

 and found by Halle at Slogget Bay in Fuegia, and closely allied to the Chilean 

 A. imbricata. 



We know nothing of the gradual changes that must have taken place from the 

 Miocene, when the climate was warmer than now, till the glacial epoch. The supposed 

 extent of the ice is shown on Nordenskjöld's map.^ According to him some parts 

 of the land along the east coast were free from ice-cover; they probably showed a 

 tundra vegetation, in which many of the species now living in Fuegia or the Falk- 

 lands may have been comprised. The forests liad been driven back farther north. 

 After the recession of the ice Nothofagus-iorests again occupied the land or at least 

 the areas now covered by them. We have hardly any knowledge of postglacial 

 climatic changes. I have dealt with this question in a note,^ as I thought that the 

 occurrence of certain species in isolated places soutli of their boundary might be 

 explained by the relic-theory so often applied for the explanation of similar facts in 



^ ilber (lie posttertiären Ablagerungcn der Magellansländer. Sv. Exp. Mag.-länd. 1895 — 97. I. 1899. 

 ^ Have mc any evidcnccs of postglacial climatic changes in Patagonia and Tierra die Fuego? (Post- 

 glaziale Kliniaveränderuugen, XI. Intern. Geol. Congress, Stockliolm 1910.) 



