186 P. A. Paly — Problems of the Pacific Islands. 



36. Stronger tilting is illustrated in the Yavau island cluster 

 of the Tonga group (fig. 35). Contrast with these cases the 

 platform sections of the undisturbed Rodriguez island (fig. 34) 

 and Mbengha island of the Fijis (fig. 38). You have already 

 noted the shelfless condition of the strongly uplifted Kambara, 

 Nauru, and Ocean islands.* 



While the existing charts thus seem to support the new 

 theory as it undergoes a very searching test, closer field study 

 of the disturbed islands is highly desirable. Specially signifi- 

 cant in each case is the question of the date of uplift or sink- 

 ing : does it fall in pre-Glacial, Glacial, or post-Glacial time ? 



7. What are the criteria for recognizing true reef forma- 

 tions in elevated islands? How thick are such uplifted reefs? 

 How extensive? What is their paleontology and what their 

 geological age ? What are the criteria for recognizing lagoon 

 deposits and talus deposits? What is the true nature of the 

 " coralliferous limestone," described in the elevated islands of 

 the Tonga, Fiji, Solomon, and other groups ? This partial 

 list of leading questions regarding these special islands will 

 suffice to point to the rich harvest of fact and deduction await- 

 ing trained observers who there have a chance to carry on sys- 

 tematic research. 



8. Finally, the new theory, like the subsidence theory, 

 should be checked by diamond-drill borings at several appro- 

 priate localities in the Pacific islands and lagoons. Plans for 

 them should certainly be included in an organized field 

 campaign. 



Review and Conclusion. 



You have now followed me through a long discussion of 

 only two of the many extant theories of coral reefs. Analysis 

 of others, like Murray's solution theory, would also suggest 

 big problems for workers in the Pacific islands. The purpose 

 of this paper, however, is not to consider theories or geological 

 problems exhaustively, but to give examples of world questions 

 that press for partial or complete answer in the Pacific archi- 

 pelagoes. Nearly all of them are taken from only one corner 

 of the field of natural history. Yery different would be the 

 emphasis of zoologist, botanist, or anthropologist who might 

 advocate my thesis. Yet I venture to hold that specialists in 

 each of these sciences would unanimously favor a workable 

 plan for the comprehensive investigation of the islands in the 

 Great Ocean. The project is clearly possible, with American 

 support and leadership. It is advisable as the most economical 

 and scientific way of advancing natural science. It promises 

 weighty results. Its accomplishment ought soon to be Ameri- 

 ca's splendid contribution to Pacific civilization. 



* See figs. 13-15, page 174. 



