162 DALY. 



of some of the existing reefs. Nevertheless, the bathometrie relation 

 of platform to reef is normally so constant in all three oceans that a 

 general explanation of reefs in terms of crustal movements seems im- 

 possible. In other words, the coral-reef problem is really the problem 

 of the platform represented in each of the many submarine shelves and 

 lagoon floors of the coral seas. Most of the reef platforms, like many 

 banks situated outside the coral seas, have such forms, dimensions, 

 and relations to the sea-level that they appear to have originated 

 during a long period of nearly perfect stability for the general ocean 

 floor. That is a conclusion forced on the writer by a close study of the 

 marine charts. Its validity is a matter quite independent of the 

 Glacial-control theory. Local uplifts and sinkings of the sea-bottom 

 have certainly taken place, at intervals during past geological time, 

 but submarine topography seems impossible of explanation without 

 assuming crustal quiet beneath most of the deep sea during at least 

 the later-Tertiary and Quaternary periods. The new theory, there- 

 fore, is based on the necessity of assuming general crustal stability 

 in the coral-sea areas during the formation of the existing reefs and 

 platform surfaces. Crustal uplift or subsidence must also be assumed 

 as affecting local areas, like the southwest Pacific, within the same 

 time interval, but these phenomena should not be allowed to obscure 

 the main truth which is legible in the bathometry of the tropical seas. 

 Finally, one cannot doubt that general sea-level has been aftected 

 by crustal movements during post-Pliocene time. Recent uplifts 

 have been demonstrated along great stretches of the continental shores. 

 So far as these have not been matched by crustal downwarps beneath 

 the ocean, such uplifts have tended to raise the surface of the ocean 

 everywhere. Hence, post-Glacial time may have witnessed a positive 

 shift of sea-level through a cause that has nothing directly to do with 

 the mere addition of water to the ocean by the melting of ice-caps. 

 A Recent rise of sea-level to the extent of a few meters, owing to post- 

 Glacial warping of the earth's crust, is quite credible. Some of the 

 submergence so conspicuous in the coral archipelagoes may therefore 

 be due to two distinct causes, both rendering unsafe the drowned- 

 valley criterion used by Dana in his advocacy of the subsidence theory. 



Earlier Statements of Elements of the Theory. 



Many authors, including Adhemar, Croll, Sir William Thomson 

 (Lord Kelvin), Pratt, Heath, Upham, Penck, Hergesell, and Wood- 

 ward, have shown the considerable deformation which must be pro- 



