Professor Hoffmann on Mont Etna. 3T7 



tion assumed the form of immense dikes rising up from below, 

 and a third represented numerous veins which traversed perpen- 

 dicularly, and in a great variety of contortions, the rocky walls 

 of the valley. 



But what was still more singular and surprising, these tra- 

 chytic beds dipped away in all directions from the sides of the 

 valley, and thus gave it the form of an amphitheatre, only that 

 a part of its eastern margin was deficient where it formed a large 

 gap. In fact, when once one has entered its interior, the idea 

 at once occurs that we are standing in the bottom of the caldera 

 of a crater of elevation . The dimensions of this crater of ele- 

 vation are quite capable of including within its bounds the cen- 

 tral volcano ; but it is curious that the latter is planted upon 

 one of the borders of this crater. For the diameter of this spa- 

 cious amphitheatre, which impressed us so forcibly, is fully five 

 miles ; and, according to our measurements, the enclosing walls 

 are 1000, and even 2000 and 3000 feet high. Their elevation 

 internally was probably much greater originally, as, for thou- 

 sands of years, the lavas which have been poured forth from the 

 summit of Etna, have been accumulated in this valley ; and even 

 now the greater part of the caldera is covered by the rough 

 lava-streams of the eruptions of 1811 and 1819, which renders 

 it very fatiguing to traverse its interior. According to our ba- 

 rometric measurements, the surface of this lava is elevated 4760 

 feet above the level of the sea. The Monte ZocclarOj from which 

 an excellent view is obtained of its interior, is elevated 5486 feet. 

 The Ciglione della Valle del Bove, and the Cima della Valle del 

 Bove, both of which are placed upon the margin, are elevated, 

 the former 8628 feet, and the latter 8808. But the present 

 summit of Etna towers to the height of 1021 2 feet. From these 

 measurements, you may form some idea of the appearance of 

 these rocky walls as seen from the interior of the Caldera. 



Catania, 

 26^ January 1831. 



