1909.] OUTLOOK OF SEISMIC GEOLOGY. 279 



With the exception of the report on Krakatoa the five mono- 

 graphs and accompanying grand atlases which have been issued by 

 the Geological Survey of the Dutch East Indies under the direction 

 of Dr. Verbeek, seem to be but little known; yet they contain the 

 results of extended and detailed surveys within one of the world's 

 most interesting volcanic regions.^'' Nowhere have such trustworthy 

 data been compiled which permit of a thorough study of the arrange- 

 ment of volcanic vents. Clearly aligned upon fissures the map of 

 Java displays the elements in the intersecting volcano network, as 

 may be seen from atlas drawings reproduced in Figs. 1-2. 



Though more accurately worked out, it does not appear that 

 these instances of intersection of volcano rows is exceptional. Felix 



9 



6 



Fig. 3. Map to bring out the arrangement of volcanic islands and submerged 

 volcanic peaks in the Lipari group. 



and Lenk-® have explained the prominence of the mighty volcanoes 

 of Mexico, Popocatepetl, Ajusko and Nevada di Toluca, as due to 

 their location at the intersection of important fissures, though the 

 warrant for this has been questioned by others. The volcanic Lipari 

 Islands of the Mediterranean, which were formerly regarded as 



°^ Verbeek, "Sumatra's Westkust " (Dutch language), Batavia, 1883, 674 

 pp., atlas of 16 maps. Verbeek, " Krakatau," Batavia, 1885, 567 pp., atlas of 

 25 pis. Verbeek et Fennema, " Description Geologique de Java et Madoura," 

 Amsterdam, 1896, two volumes, 1,183 PP-) atlas of 24 maps. Verbeek, " De- 

 scription Geologique de I'ile d'Ambon," Batavia, 1905, 323 pp., atlas of 10 

 maps. Verbeek, " Rapport sur les Moluques," Batavia, 1908. 1844 pp., 

 atlas of 20 maps. 



^ Zcitsch. d. deutsch. geol. Gescll, Vol. 44, 1892, pp. 303-326. 



