Not at all startled or suprised am I, bij these forma- 

 tions. In ,the time or era, wherein tlie supermariiie portions 

 of the earth's ernst "were breken up and down, and the ren- 

 dings filled in with iiquid molton rock from below (forming 

 the basaltic djkes occurrent in the coal measiires &c) , no plau- 

 sible reason can be assigned for assuming, that the submarine 

 portions were not in the same era likewise convulsed and bo- 

 dies of Iiquid molten rock consequently bursting upwards tlirough 

 these rendings, the hydrostatic pressure on the sides of which, 

 and the cooling of their exteriors into solid shells, would cause 

 their interiors to rise upwards, in forms corresponding to the 

 forms of the openings, through which they w^ere issuing, whilst 

 the vast pressure of the ocean on its bottom around or along 

 those uprising portions, would force the iiquid metal, or 

 rock on its upward progress; these forms of course varying 

 from circular and sinuous, to straight lines or nearly so. Whcn 

 these erupting masses became so much elevated, that the hy- 

 drostatic pressure upon their sides and tops failed to counter- 

 balance the outward and upward pressure of their interiors, they 

 would burst open , the openings of the circular forms (or nearly 

 so) becoming submarine craters and the dyke forms, splitting 

 and in part falling outwards into the adjacent depths of the 

 ocean. 



Iir. » The verj general surprise of all tbose -vrho have beheld LK^ooa 

 » islands , has perhaps been oae chief cause , why other reefs of an equally 

 scurious structure, have beea almost overlooked. I allude to the cncirclin{j 

 » reefs. We will take as an iastance, Vanikoro , celebrated bi) the ship- 

 j> wreek of La Peeoüse. The reef there runs, at the distance of nearly 

 3>lwo and in soiue paris three miles from the shore , and is separaled from 

 » it by a channel, having a general depth of between thiity and forlyfalhoms 

 »and in ene part no less than üfty or three hundred feet. Externaliy, 

 »the reef rises from an ocean profoundly deep. Can anything be more sin- 

 » gular than this structure? 



sit is analagous to that of a lagooa , but with an island standing in the 

 smiddle, like a picture iu a frame. A strip of low alluTial land in these 

 » cases generaliy surrounds the base of the mountains; this, covered by 

 T> the most beauliful produclions of a tropical land , backed bij the abrupt 

 3 mountaias , and fronted by a lake of smoolh water , only separated from 

 ïthe dark waves of the oceaa bij a line of breakers , forru the clements 



