212 REACTION OF THE INTERIOR OP THE EARTH 



western declivity of the Peruvian chain of the Andes. The 

 travertin of Van Diemen Island (near Hobarton), contains, 

 as we learn from Charles Darwin, the remains of vegeta- 

 tion belonging to the earlier ages of the world. It may be 

 noticed, that lava and travertin, which are rocks still formed 

 beneath our eyes, present to us the two extremes in geologi- 

 cal relations. 



The phenomena of nrad volcanoes are deserving of more 

 attention than geologists have hitherto given to them ; their 

 grandeur has been overlooked, because, of the two phases 

 presented by them, it is only the second, or calmer state, 

 lasting for centuries, which has usually been described : but 

 their origin is accompanied 'by earthquakes, subterranean 

 thunder, the elevation of great districts of country, and lofty 

 jets of flame of short duration. When the mud volcano of 

 Jokmali, on the peninsula of Abscheron, east of Baku on 

 the Caspian Sea, was first formed, on the 27th of No- 

 vember, 1827, flames blazed up to an extraordinary height 

 for a space of three hours, and during the following twenty 

 hours they rose about three feet above the crater from 

 which mud was ejected. Near the village of Baklichli, west 

 of Bacu, the column of flame rose so high that it could be 

 seen at a distance of twenty-four miles. Enormous frag- 

 ments of rock, torn doubtless from depths, were hurled to a 

 great distance round. Similar fragments are seen around the 

 now tranquil mud volcano of Monte Zibio, near Sassuolo ii 

 Northern Italy. For fifteen centuries, the Silician Salse 

 near Girgenti (Macalubi), described by the ancients, has 

 continued in the secondary stage of activity ; it consists of 

 several conical mounds, from eight or ten to thirty feet 

 Ingh, subject to variation both in form and height. Streams 

 of argillaceous mud, accompanied by periodical disengage- 



