TRUE VOLCANOES. 347 



extremity of Java the mean axis runs somewhat more to- 

 ward the north, nearly E.S.E. and W.N.W., while from the 

 Strait of Sunda to the southernmost of the Nieobar Isles the 

 direction is from S.E. to N.W. The whole volcanic fissure 

 of elevation (E. to AY., and S.E. to N.W.) has consequently 

 an extent of about 2700 geographical miles, or eleven times 

 the length of the Pyrenees. Of this space, if we disregard 

 the slight deviation toward the north in Java, 1G20 miles 

 belong to the east and west direction, and 1080 to the south- 

 east and northwest. 



Thus do general geological considerations on form and 

 range lead uninterruptedly, in the island world on the east 

 coast of Asia (over the immense space of 68° of latitude), 

 from the Aleutian Isles and Behring's Sea to the Moluccas 

 and the Great and Little Sunda Isles. The greatest variety 

 in the configuration of the land is met with in the parallel 

 zone of 5° north and 10° south latitude. It is very remark- 

 able how generally the line of eruption in the larger portions 

 is repeated in a neighboring smaller portion. Thus a long 

 range of islands lies near the south coast of Sumatra and 

 parallel to it. We find the same appearances in the smaller 

 phenomena of the mineral veins as in the greater ones of the 

 mountain ranges of whole continents. Accompanying debris, 

 running by the side of the principal vein, and secondary 

 chains (chaines accompagnantes) lie frequently at considerable 

 distances from each other. They indicate similar causes and 

 similar tendencies of the formative action in the folding in of 

 the crust of the earth. The conflict of powers in the con- 

 temporaneous openings of fissures in opposite directions ap- 

 pears sometimes to occasion strange formations in juxtapo- 

 sition, as may be seen in the Molucca Islands, Celebes, and 

 Kilolo. 



After developing the internal geological connection of the 

 East and South Asiatic insular system, in order not to devi- 

 ate from the long-adopted, though somewhat arbitrary, geo- 

 graphical divisions and nomenclature, w r e place the southern 

 limit of the Eastern Asiatic insular range (the turning-point) 

 at Formosa, where the line of direction runs off from the 

 N.E.— S.W. to the N. — S., in the 24th degree of north lati- 

 tude. The enumeration proceeds again from north to south, 

 beginning with the eastern, and more American, Aleutian 

 Islands. 



The Aleutian Isles, which abound in volcanoes, include, 

 in the direction from east to west, the Fox Islands, among 



