452 Evolution and Distribution of Fishes 



of these strata gave rise to the Western Andean range, 

 while the numerous volcanic peaks along that range attest 

 the mighty character of the disturbances. 



Many of the plants then, from Miocene time onward, 

 along the elevated area of this land mass, as well as east- 

 ward along the Falkland and Crozet line, took on, if they 

 had not already assumed, the subalpine to alpine character 

 that they now possess, though along its lower reaches, and 

 especially along the northern edge of the South Continent, 

 mild to warm-temperate conditions probably prevailed. 



During the late Cretaceous or very early Eocene period, 

 the South Continent probably had its most extensive east- 

 ward continuation to N. Zealand, and then permitted the 

 species Galaxim attenuatiis to extend its area from S. 

 America to S. E, Australia, N. Zealand and Tasmania. In 

 transit, and while exposed to changing environal states, 

 Galaxias (Fig. 71a, p. 462 doubtless evolved new species, 

 some of which entered or originated in N. Zealand and Tas- 

 mania. It also permitted Prototroctes to reach the former 

 area, while Aplochiton seems to have lagged behind in S. 

 America, or has been blotted out over the Southern Con- 

 tinent. But at this time the marsupials had not reached 

 either centre, though moving across the continent. 



A break between the N. Zealand-Norfolk Island area on 

 the one hand, and the Tasmano-Australian area on the other 

 seems now to have been effected, and during late Eocene 

 to Oligocene time, the polyprotodont marsupials entered 

 by Tasmania and S. E. Australia. It is not unlikely how- 

 ever that during the journey across the South Continent, 

 specializing side members from the polyprotodonts may 

 have attained to the diprotodont stage of specialization. 



As proving the climatic and nutritive possibilities for the 

 production of such results as the above, and also from re- 

 sults secured by the Swedish South Polar Expedition (279) 

 and others, we now know definitely that during the Cretace- 

 ous and again during Tertiary time, comparatively mild 

 conditions prevailed even in Graham's Land, in Seymour 

 Island, and probably on to or near the South Pole. Also 

 that such was accompanied by an abundant and varied 

 temperate or warm temperate flora. Thus Halle in his 



