ARTICLES 



43i 



investigation seems to have been little, if any, greater than that 

 of his German predecessors. He argued against the theory of 

 subsidence on the ground that volcanic islands ought to occupy 

 areas of elevation, and that subsidence should be expected only 

 in the intermediate oceanic areas ; he thought that barrier reefs 

 were formed by outgrowth around stationary islands ; he failed 

 to recognise that, if barrier reefs were thus formed, the fringing 

 reefs and the lagoon limestones inside of the barrier reefs should 

 rest conformably, as in section M, Fig. 2, on the non-eroded 

 submarine extension of the island slopes ; that the islands 

 should not have embayed shorelines ; and that extensive deltas 



Fig. 2. — Sector diagram, illustrating successive stages of atoll development by the out- 

 growth of a barrier reef around a still-standing volcanic island, which is gradually 

 worn away. 



Note the increasing width of the alluvial plain fronting the non-embayed mountain base in sectors h and J ; 

 the reduction of the island to a lowland in sector K, and the removal of the lowland in sector L. The 

 outgrowing reef rests on its advancing talus, and the talus rests conformably upon the non-eroded 

 submarine slope of the volcano, as in section M. No reef-encircled islands are known which present 

 the features shown in sectors h, j, k, or l. Islands within barrier reefs usually have tapering spurs 

 advancing between drowned-valley embayments, as in sector o. 



should stretch forward from simple shorelines into wide lagoons, 

 as in sectors J and H ; and he failed also to recognise that the 

 facts contradict these essential consequences of his theory. He 

 believed also that lagoons were excavated by solution, although 

 lagoon floors give no indication of such origin, for they are 

 covered with accumulating calcareous deposits ; and he even 

 suggested that outgrowing barrier reefs might be converted 

 into atolls by the gradual wearing down of their stationary 

 central islands, although no example of a transitional stage, 

 in which the central island is worn down to low relief and 

 surrounded by delta piains, as shown in sector K, Fig. 2, is 

 known. 



