glkcial period, the ice retreated northwards and up into the mountains, followed by the 

 arctic and subarctic flora, giving way to a steppe vegetation, which little by little immi- 

 grated into the dry south Siberian lowland, and isolated this arctic and subarctic floral 

 cdlony to the south. 



In this connection I will also call to remembrance that among the plants already 

 reported from the low-lying and dry steppe regions about Minusinsk, at an altitude of 

 about 250 m. above sea-level, also some arctic and high northern plants were found by 

 me, for instance: 



Putrinia siberica, Asler alpinus, Carex capillaris subspec. densiflora nov. subspec, 

 Stellaria Bungeana var. latifolia. Primula sibirica, Carex alro-fusca var. coriophora, 

 Stellaria petraea, Potentilla sericea, Stellaria crassifolia, Myosotis silvatica, Lilium 

 Martagon, Cobresiaspec, Arctogerron gramineus, Scorzonera radiata, Moehringia lateriflora, 

 and others 



They occur here most frequently in small, scattered colonies within limited areas, 

 especially in moist places, or also on the ridges of the sandstone hills, often together 

 with solitary larches, surrounded on every side by the common xerophile vegetation 

 of the steppe. 



These plants should possibly be regarded as remnants from the flora of the former 

 colder period in these regions, which have been able to survive here in the lowland, all 

 of them being plants the geographical range of which mainly lies in northerly regions 

 or in alpine and more elevated mountain tracts, in the same way as I consider the 

 larches here to be the last remains of the forests of the past in these tracts. 



Similar plants of the high North may also no doubt be found in many other places 

 on these low-lying steppes. We know, it is true, that during the glacial period proper, 

 large portions of the Siberian lowland here were covered with a great ocean, to the north 

 connected with the northern Arctic Ocean, and to the south extending right down 

 to central Asia, to the Caspian and Areal Sea, forming at this time a boundary between the 

 vegetation of Europe and that of the remaining parts of Asia. As far as to its most 

 southern limit this ocean must have had a perfect arctic character, for in the deeper 

 parts of the Caspian Sea there are still to be found, according to what G. 0. Sars has 

 pointed out, arctic marine Crustacea, relicts of the arctic animal life which was pre- 

 dominant here at this time. When the sea receded from here, the climate must, howe- 

 ver, in my opinion, still have been rather cold, and the flora and fauna immigrating 

 and taking possession of this old, drained sea-bed, has been, albeit perhaps no longer 

 absolutely strictly speaking arctic, at least of a high northern character. 



This is evident from the remains of mammoths — d6bris of a fauna of the high 

 North — which are of rather common occurrence in Siberia, and, lying upon these 

 marine deposits, they are, accordingly, younger than this glacial transgression of the 

 ocean. The remains of the mammoth, thus belonging to the younger Tundra stratifi- 

 cations, are to be found not only in northern Siberia but occur right down to the extreme 

 south, as for instance also at Kushabar, where the year before our stay there, remains of 



Kemains ot a 

 flora of the high 

 North on the 

 steppes of sou- 

 thern Siberia. 



39 



