OOQ 



tion marked in the elaborate and beautiful map of tbe^ 

 Government Surveyor, Mr Corby, drawn from surveys 

 made in the year 1857, stretching into the sea from 

 the point on which numerous trunks of trees are found, 

 is already broken up into several huge masses which are 

 almost covered by the sea ; and the point itself being 

 to a great extent undermined by the violence of the 

 waves must ere long be swallowed up in the same 

 manner. 



I have already said that no sea-shells are discover- 

 able in this stratum although abundant-in the coral 

 stratum immediately beneath it ; but these are replaced 

 by two land shells, the presence of which is of great 

 interest as I shall presently shew. The two speoies of 

 land- shells are each of them very abundant and distri- 

 buted among the roots of the trees ; — they are Cara- 

 colla Lestcri and Helix riifa. — The Caracolla still ex- 

 ists in the living state on both islands ; in great abun- 

 dance in the cocoas and vacoas on Flat island ; but I 

 have not been able to discover a single recent living or 

 dead shell of the Helix on either of the islands al- 

 though I searched most carefully for it during a re^ 

 sidence of several months ; and I do not believe that 

 this shell would have escaped my search bad it still 

 continued to exist. The same species is however suffi- 

 ciently common in the living condition in Mauritius. 



Before I quit the description of this formation I may 

 state that I carefully looked for it around the shores 

 of Flat island ; but was able only to detect the traces 

 on the rocky shores of a small sandy bay at the east-, 

 ern base of the Light-House mountain ; and it is by no 

 means improbable that at this moment every trace has 

 disappeared. 



It is not however, around the shores only of Gabriel 

 island that this formation is found. Detached blocks 

 of large size are seen on the eastern size at thirty or 

 forty feet above sea-level ; and one black weighing 

 from one to two tons lies near the highest point of the 

 island about 80 feet above the sea. 



In the foregoing pages I have confined myself strictly 

 to a descriptiou of the conformation of the two islands. 

 \ now proceed to an examiuatiou of the changes which 



