488 THE CONTINENTAL ORIGIN OF FIJI, 



of heavily faulted crystalline rocks, upon the flanks of which 

 marine sediments of Mesozoic and Eocene age have been laid to 

 a considerable thickness. The Mozambique Channel forms an 

 immense "Senkungsfeld," a huge slice of the earth's crust which 

 has been let down by a series of trough faults. On the island of 

 Madagascar the aggregate throw of these faults on the eastern 

 side of the island amounts to 1200 meters. Marine strata of 

 Cretaceous age have been let down by the faulting, proving that 

 the crustal movements are Post-Mesozoic in age. 



In the case of the South- Western Pacific area, we have several 

 points in contrast to those mentioned above. In the first place, 

 the distances between the islands are much greater than in the 

 West Indian area, and the intervening depths are very consider- 

 able. In the second place, the existing land masses are very 

 insignificant when compared with the bulk of Madagascar. 



The first consideration is, to my mind, the more serious, 

 involving as it does the question of the permanence of the ocean 

 basin in the area to the west of Fiji. 



It has been suggested that the occurrence of granites and other 

 plutonic rock in Fiji might be explainable on other than a 

 continental hypothesis, by regarding them as having been 

 injected during late geological time into a mass of volcanic 

 material built up from the floor of the deep ocean; an ordinary 

 oceanic island, in fact. This leaves out of consideration the exten- 

 sive quartzites which occur on the island. 



The evidence as to the age of the granites is also fairly con- 

 clusive. On lithological grounds, the age of the rocks in question 

 seems to be great. They are so intensely jointed, and show so 

 manv evidences of great earth-movement. Of course, strain- 

 structures do not necessarily indicate ver}^ high geological 

 antiquity, as is evident from the occurrence of Mesozoic schists 

 in the Alps. In the latter case, however, we have to deal with 

 an area where great folding has taken place in late geological 

 time, and, at present, we have nothing to justify the supposition 

 that intense orogenic processes have been going on in the Fijian 

 area. 



