234 POPULAR SCIENCE MONTHLY. 



ent geological relation. The oxide and carbonate are associated 

 with dolomitic limestones of the lower Devonian, and may be traced 

 into them by a gradual transition, as at the mines of Bakal, where 

 the ore is hematite for some distance below the surface, then passes 

 to spathic iron, and this into dolomitic limestone at a considerable 

 depth. 



After traversing the Urals to Zlatoust, where are the great iron 

 and steel works that produce some of the finest weapons used in the 

 Russian army, and that sent an elegant exhibit to the Chicago 

 World's Fair, the excursion traversed the famous mining and mineral 

 region of the Ilmen Mountains northward to Tagilsk and Ekaterin- 

 bourg. This portion of the route is treated of in several papers as 

 follows: The Eastern Slope of the Urals (No. 5), by Prof. A. Kar- 

 pinsky; The Minerals of Kussa and Miass (No. 4), by A. Arzruni; 

 The Gold Deposits of the Southern Urals (No. 6), by N. Wyssotsky; 

 The City of Ekaterinbourg and its Environs, especially in Reference 

 to Prehistoric Archaeology (No. 7), by Dr. O. Clerc; The Mining 

 Districts of Tagil and Gora-Blagodat (No. 9), by Professor Tscher- 

 nitschew; and one or two minor articles. 



Professor Karpinsky gives an admirable account of the region 

 of the eastern Urals and beyond, emphasizing the contrast between 

 the two sides of the system. While the western slope passes by 

 gradual and gentle undulations into the plains and steppes of Eu- 

 ropean Russia, the Asiatic side has been enormously eroded away. 

 A wide belt of country along the eastern base of the Urals, consist- 

 ing of upturned and folded rocks identical with those of the moun- 

 tains, has been leveled down to an absolute plain. Over this are 

 spread the deposits of the Tertiary sea that reached in Pliocene 

 time nearly to the central ranges of the Urals, and that has largely 

 obliterated their eastern portion. These deposits stretch far away 

 into the great Siberian plain. Along their western edge, and for 

 some distance eastward, they are strewn with lakes some fresh and 

 some salt ; some deep and narrow among the folds of the edge of the 

 mountain region; others broad, shallow, and with flats and benches 

 of gradual contraction in the level country to the east. Two strik- 

 ing views of this lake-bestrewn plain from the top of some of .the 

 Ilmen peaks are given in the monograph. 



The gold of the Urals, of course, receives much attention in 

 these papers; the placers are carefully described, and the quartz 

 mining also, which in some districts is overtaking and surpassing 

 the placers in output. Closely connected with these are the plati- 

 num workings, thus far wholly surface deposits. But it is of great 

 scientific interest to note the definite tracing of this metal to its origi- 

 nal rock source, associated with chromic iron in serpentines, which 



