Daly — Pleistocene Glaciatiou and Coral Reef Problem. 307 



But, granting: (1) a very slow rise of sea-level during the 

 late Pleistocene, (2) an early colonization of the Maldive plat- 

 forms, and (3) lateral growth of a reef at a rate much faster 

 than the drowning (a most probable assumption): we can 

 imagine a late Pleistocene coral patch soon spreading "like a 

 fairy ring" to the size and shape of a "faro" atoll. That the 

 "faros" are concentrated on the edges of the platforms is a 

 natural and well recognized effect of the conditions of coral 

 growth. 



Smnviary of Conclusions. — A statement of the view that 

 most atolls and barrier reefs were formed during a period of 

 relative crustal repose is not complete until the effect of the 

 Pleistocene lowering and subsequent swelling of the equatorial 

 vpaters is considered. Since the positive movement of sea-level 

 was not general, being ofliset in higher latitudes by the annul- 

 ment of glacial attraction, the effect in the intertropical seas 

 may be described as a heaping or ^-i^mwZar movement of water 

 above the antecedent geoidal surface. To that tumular move- 

 ment the peculiar forms and relations of atolls and barrier 

 reefs are directly attributed. This idea obviously in no sense 

 excludes complications due to local warpings of the earth's 

 crust, with, for example, negative movement of sea-level in 

 Fiji and positive movement at the Great Chagos Bank. The 

 changes in sea-level due to glaciatiou and subsequent deglacia- 

 tion have been discussed as though other processes had not 

 affected general sea-level. They have been so far neglected in 

 the argument because of the high probability that neither 

 basin-foundering, nor sedimentation, nor absorption of water 

 by weathering rocks seem to have been important enough, 

 since the Tertiary, to affect, by more than a fathom or two, 

 the changes of level assumed. 



The related view, that most of the great plateaus now bear- 

 ing atolls and barrier reefs were finally truncated by Pleisto- 

 cene marine erosion, explains the remarkable flatness of these 

 platforms and their nearly uniform depth of 45 to 50 fathoms. 

 As Suess points out, these features can hardly be explained, 

 either on the Darwin-Dana hypothesis or on Murray's hypo- 

 thesis of solution inside the reef. Murray's conception, that 

 many of the plateaus have been built up by calcareous 

 accumulations on volcanic peaks which, by eruptions, had 

 reached to depths within a few hundred fathoms of the sur- 

 face, is in. ill adjustment with his solution hypothesis. In any 

 case it cannot solve the problem for the vast majority of reef- 

 bearing plateaus. 



Since reef-building corals doubtless flourished in the equa- 

 torial seas during the Tertiary period, and there greatly 

 protected island and mainland from wave attack, the develop- 



