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IOWA ACADEMY OF SCIENCES. 



of steep-sided hills, or mountains, each isolated from the 

 others. The principal town of the region is Piatigorsk, 

 which is about ten miles from the railway station of Mine- 

 rain iy a Vody. 



The purpose of referring at this time, to these hills,which 

 reach elevations from 1,500 to 2,500 feet above the plain 

 (figure 5), is to call attention to certain geological phe- 

 nomena that are unusually well developed; and incidentally 

 to exhibit photographs of the highest mountain peak in 

 Europe, which is nearby. 



Figure 5. Volcanic necks of Piatigorsk, four miles away. 



The plain around Piatigorsk is made up of flat-lying 

 Tertiary deposits. Out of these rise the isolated volcanic 

 mountains, composed mainly of white or gray trachytes. 

 The ash and scoriaceous materials have all been removed, 

 leaving the harder lavas which occupied the pipes of the 

 vents and the central parts of the cones, standing out in 

 abrupt mounds. These vents appear to represent the 

 dying stages of the great outburst which gave birth to the 

 towering volcanic cone of Mt. Elburz, twenty miles distant. 



Authorities have long considered Mt. Blanc, in the Alps, 

 to be the highest point in all Europe. Its height above 

 sea-level is placed at 15,780 feet. Recent measurements 

 show that the Caucasus mountains present no less than 

 five peaks, every one of which is more elevated than any 

 part of the Swiss district. 



Mt. Elburz is an isolated cone on the north flank of the 

 great Caucasian chain, and rises to a height of 18,526 feet 



