QUAliTERLY JOURNAL 



THE GEOLOGICAL SOCIETY OF LONDO!^. 



PROCEEDINGS 



OP 



THE GEOLOGICAL SOCIETY. 



May 8, 1872. 



William Edward Balston, Esq., B.A., of Thornhills, Maidstone, 

 was elected a Fellow of the Society. 



The following communications were read : — 



1. Notes on Atolls, or Lagoon-islands. By S. J. "Whitnell, Esq. 



(Communicated by Prcf. Maskelyne, F.R.S., F.G.S.) 



[Abstract.] 



These notes are founded upon an examination of sixteen atolls in 

 the Union, Ellice, and Gilbert (or Kingsmill) groups. The author 

 is of opinion that, although the production of atolls is due to sub- 

 sidence, a cessation of this subsidence is necessary in order to their 

 emergence from the sea. He argues that, as the islands formed 

 upon the reefs of atoUs consist entirely of broken coral, shells, and 

 fine sand, it seems improbable that such materials should accumulate 

 upon a sinking surface ; or if they did temporarily collect, owing 

 to certain favourable conditions, they would soon be washed away 

 again by the waves. At Funafuti (or Ellice Island) he noticed what 

 he regards as signs of upward movement. On the weather side of 

 the largest islet in this atoll there is a small lagoon (dry at low 

 water) shut in from the sea by a wall, 20 feet high, of large masses 

 of coral. The reef forms a narrow ledge, upon which the author 

 saw compact masses of coral, in situ, rising 4 feet above low-water 

 mark. 



vol. XXVIII. PAET I. 2 E 



