ipop.] 



OUTLOOK OF SEISMIC GEOLOGY. 



281 



in a noteworthy compilation^- has shown that these directions are 

 brought out for the African continent not only in the lines of 



Fig. 4. Volcanotectonic lines which cross at St. Helena. 



volcanoes but by the fracture systems revealed in the rocks, so far 

 as they have been studied. It is interesting to note that these 



^' " Der aktive Vulcanismus auf dem Af rikanischen Festlande und den 

 Afrikanischen Inseln," Munchener Geographische Studien, No. 18, 1906, 

 218 pp. 



