THE 



EDINBURGH NEW 

 PHILOSOPHICAL JOURNAL. 



On Volcanos and Craters of Elevation. By Leopold Von 



Bitch. 



The tour which I made in the autumn of 1834, with Pro- 

 fessor Link and M. Elie de Beamnont, and afterwards also with 

 M. Dufrenoy, enabled us to determine more exactly some of 

 those relations of elevation-craters, of which T formerly treated 

 in the Academy, seventeen years ago, and also in my work on 

 the Canary Islands. 



Volcanos are the constant chimneys, the canals uniting the in- 

 terior of the earth with the atmosphere, which spread around 

 themselves the phenomena of eruption from craters that are of 

 small extent, and are only once in operation. Craters of eleva- 

 tion, on the contrary, are the remains of a great display of 

 power from within, which can and actually has raised islands of 

 several square miles in extent, to a considerable height. They are 

 conical and very extensive circular enclosures (umgebungen), with 

 strata, which internally seem horizontal, but which on all sides 

 dip to the exterior in a mantle-shaped manner. From such en- 

 closures proceed no eruptive phenomena, there is no canal con- 

 necting them with the interior, and it is only rarely that we find 

 in the vicinity or in the interior of such a crater traces of vol- 

 canic activity still in operation. This difference seems to me 

 more an observation than a hypothesis. It is the separation of 



VOL. XXI. NO. XLII.— OCTOBER 1836. O 



