Barrier Reefs of Tahiti and Moorea

Abstract

To answer completely the letter from Prof. Davis, published in NATURE of Sept. 3, would take too much space, so, as he suggests, I leave my papers to speak for themselves when they appear. To explain the presence of basaltic stones on the ‘barrier’ reef by a filling in of the lagoon, and its re-excavation, is really a special pleading against the simpler hypothesis of a once continuous reef; I can myself suggest a much simpler alternative, namely, by their being floated across entangled in the roots of trees, floated out to sea by floods. I reject this means of transport, however, because the stones are invariably rounded, which could only be the ease when the tree has been uprooted from an alluvial flat. The reefs and their embedded stones are certainly pre-glacial, when such flats were of small extent, especially if, as Prof. Davis holds, the valley mouths were drowned, and the stones, in the great majority of cases, could have been only angular fragments of the rocky sides of torrents.