1897.] NATURAL SCIENCES OF PHILADELPHIA. 423 



from the west there is nowhere the bold, rugged landscape that one 

 sees iu the Caucasus or in Switzerland. It is only by looking back 

 on the steep basset edges of the formations that one realizes the 

 mountainous character of the region. But starting from Ourjum 

 to cross the Eur-Asian line, and descending from that line into 

 Siberia towards Miass the mountainous character is lost altogether. 

 As M. Karpinsky justly says (L. G., V. 2) : " On the east slope 

 and at a short distance from the axis the region loses almost at once 

 its mountainous character so completely that, though its geological 

 structure corresponds with a very complex mountain region, the 

 greater part of it presents an area so flat that the relief is less 

 accidented than that of most of the plains of European Russia." 



It is like entering the basement of a house built on the steep side 

 of a hill and climbing to the roof to find that a broad plain stretches 

 itself out from that level. This is the first feature to strike the 

 observer. The second is a corollary of the first, namely the infre- 

 quency of exposures. The third is the enormous development of 

 lakes. At least one-third of the surface of these steppes is covered 

 by water which is supplied from countless bogs and morasses lying 

 in all positions on the east side of the chain from close up to the 

 axis to a distance further than the eye could see. 4 It has been 

 mentioned that the water courses of the western half in their incep- 

 tion follow the longitudinal valleys parallel with the axis of the 

 chain for considerable distances and with considerable rapidity 

 before breaking through the transverse gorges of about 10 wersts or 

 kilometers more or less in length to the main water arteries on 

 the trans- Volgian steppes. The reverse is the case with the Siberian 

 streams. With a very few exceptions their early course is directly 

 away from the axis of the chain, and the flow is parallel to circles 

 of latitude for a very considerable distance. Over this part they 

 flow sluggishly from and through impassable swamps, showing few 

 or no outcrops on their banks. The outcrops occur on the com- 

 paratively elevated country between the water courses. 



On the other hand, in their middle course (which the excursion- 

 ists could not observe) the outcrops of rock in place are reported as 

 commencing to appear in isolated places, becoming more and more 

 frequent, and finally uniting in a continuous outcrop. The river is 



4 The characteristic features of the water courses to the east are taken from 

 theLivret Guide, as the course followed by the excursion did not permit the 

 participants to actually see the second and third divisions here referred to. 



