.{OSS ON TAnALLEL LIiYES OF i^LEVATIOX. 135 



volcanic phenomenfi are still luore remarkable, niid when these 

 intersecting axial lines are those of the latest (and greatest) zones, 

 the result is the most extensive and intense disphn- of voicanic 

 acti\ ity v^^hic]? exists on the earth. Thus the intersections o^ the 

 axial lines of /.ones Nos. L, 2, and 3 produce, in the East Indian 

 Archipelago, the most volcanic region of the earth, and their 

 antipodcil intersections produce in Mexico, Central America, the 

 Northern Andes, and the lesser AVest Indio Islands, the onlv other 

 volcanic region at all approximating to io in extent and activity. 

 The intersection of zones i^Tos. 2, 4, and 5, gives the volcanic regions 

 of the Azores and Canary Islands. (See Plate I. Fig. 3.) Their 

 antipodal intersection in Tasmania though indicating great volcanic 

 activity formerly, is not novv^ activelj'- volcanic : but the intersection 

 of the {'xi?J line of zone No. 2, with the great New Zealand subzone 

 of No. 5, is marked by p, high degree of volcanic activity. The 

 intersection, apparently at one point, of zones Nos. 5, 6, 7, produces 

 the exceedingly active volcanic group of the Hawaiian or Sandvvdch 

 Islands. (See Plate 2.) Their antipodal intersection is in the 

 unexplored interior of South Africa. 



V\ here the axial lines of two zones intersect each other the 

 volcanoes are found along the axial line of the older ; thus where 

 the axial line of zone No. 1 intersects that of zone No. 3, we find 

 in ^Texico a line of active volcanoes across the country in the line 

 of No. 3, and. in Java the result is similar. At the intersections 

 of the axial lines of zone No. 1 with that of zone No. 2 we find the 

 volcanic lines of the Northern Andes, and Sumatra in the axial line 

 of zone No. 2. 



A¥here three axial lines intersect each other at, or near, the same 

 point, the volcanoes are found along the axial line of the oldest 

 zone, though the systems of parallel lines of fracture of the other 

 zones are very apparent ; thus in the Hawaiian Islands (see plate 

 No. 2) a line extending along the northern volcanoes of Hawaii to 

 the northern volcano of Ohau, represents the direction of the 

 axial line of the oldest zone — zone No. 7 ; while the other systems 

 of parallel lines marked on the map represent the lines of fracture — 

 that, is the directions of the lines of elevation of zones Nos. 5 and 6. 

 Fig. 3, Plate No. 1 represents the direction of the lines of eleva- 



