ANALYSIS OF ISLAND FORMS
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tion reef upgrowth and lagoon infilling among the various methods of platform production can therefore be regarded only as meaning their exclusion; indeed, lagoon infilling is elsewhere explicitly excluded from considération; it is directly asserted that ' ' none of the . . . platforms were formed by infilling behind a barrier reef, ' ' and it is even thought that no one would try to explain them ' ' as the resuit of infilling behind barrier reefs: they are submarine plateaus, leveled by planation agencies, which almost certainly were both subaerial and submarine, and they have been submerged in Recent geological time. " And, as if in further evidence of the inefficacy of lagoon infilling, it is urged that ' ' no evidence has yet been presented to show that any barrier reef began to form as a fringing reef on a sloping shore and was converted into a barrier reef by [upgrowth during] subsidence. " EVIDENCE FOR THE CONCLUSION HERE PRESENTED
It has not been without serious consideration of Vaughan's view that my very différent view of the circuminsular banks of the Lesser Antilles, above set forth, has been adopted. The two views agree in only one respect ; namely, that the présent reefs are based on platforms in the production of which they, the existing reefs, took no part ; but they differ widely as to the manner of platform production ; reef upgrowth and lagoon infilling being rejected in one view and being accepted as leading and essential processes in the other. The following lines of evidence have