The Bei-kem flows here in some places between high cliffs of sandstone or through 

 an alluvial plain, through which it has dug out a bed between high, sandy, terraced 

 banks, where the river erodes. In other places where the valley is more open and broad, 

 the river has formed large, flat, moist or even quite swampy flood-plains. Similar moist 

 flood-plains occur near Ust Tara-kem, and on the Dora Steppe at Petrow and 

 MosGALEWSKi. These swamps are here densely overgrown with vascular plants and 

 contain an exceedingly rich flora of algae, described by me in an earlier publication. 



Fig. 55. From the Upper Bei-kera, near the Dora Steppe. The banks grown chiefly with larch 

 and birch, In the background dry and scorched slopes of Devonian sandstone. 



In this region the Bei-kem valley lies at a height of from 800 — 940 m. above sea-level. 

 The alluvial sand terraces, with a nearly park-like appearance, being large and level 

 with scattered larches, contain, besides some of the above-mentioned plants frequently 

 occurring in larch-wood, also Leontopodium alpinum var. sibiricum, being a very 

 common and characteristic constituent of the flora, as for instance on the wide sand terra- 

 ces about the river li. In wood constisting of larch, Betula pubescens, and Populus 

 tremula, the ground is found over large stretches to be grown with Polygonum undulatum 



86 



