I'.eiiKiins ot ;i 



glacial period, the ice retreated norlliwards aiul up into tin- inouiitains, followed by the 

 arctic and subarctic flora, S'ving way to a steppe vegetation, which little by little immi- 

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

 colony to the south. 



In this connection I will also call to rcnuMubrance that among tiie plants already 

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



about '2')() 111. above sea-level, also some arctic and high norlliern plants were foinid by '^'"'■"» °" "'« 

 ,■ . . " siciipt's of sou 



me, lor instance: ., .... 



lliern Siljcria. 



Pulrinia siberica. Aslcr alpinus, Carex capillaris snbsprr. demiflora two. siihspcc. 

 Slellnrid Ihmgediui var. lalifolin. Primula sihiiint. Carex alro-fiisra inir. coriopliora. 

 Sli'llaria prirara, Polcniilla sericea. Slrllariu crassifulia, Mi/usulis siliHilica. Liliiiiu 

 Martafion. Cobresiaspec, Arctogerron gramineus, Scorzonera radlata, Mochringia lalerijlora. 

 and otiiers 



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

 especially in moist places, or also on the ridges of the sandstone lulls, 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 — debris of a fauna of the high 

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

 marine deposits, they are, accordingly, j^ounger 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 



39 



