Professor Silliman's Geological Notes. 145 



Somma. It here poured out a tqrrent of scoriaceous red 

 lava through a well-defined canal. This is now entirely cold, 

 and we collected from its sides abundant specimens of aphthi- 

 talite, which frosted over the rugged cavern like snow. Near 

 this spot also are two fumeroles formed during the last erup- 

 tion ; the largest about 25 feet high, with an aperture of 

 near ten feet, its outer walls black, rugged, and forbidding. 

 The flow of lava from the eruption of 1849 was in the direc- 

 tion of the ancient Pompeii, and it was copious enough to de- 

 stroy a small village with its vineyards, at the distance of 

 several miles. The king of Naples has since erected a new 

 village for the unfortunate inhabitants near the site of the 

 former one. 



During the past six years the king of Naples has also 

 constructed a carriage road up the side of Vesuvius as far as 

 the Hermitage, where he has a Royal Meteorological Obser- 

 vatory, under the direction of the celebrated Melloni. This 

 road follows in a very serpentine path over and around the 

 hill of ashes, which all who have seen Vesuvius will remem- 

 ber as forming a remarkable feature in its topography. In 

 this manner, sections have been opened in the hill for a dis- 

 tance of three or four miles, and were these viewed without 

 reference to the immediate proximity of the volcano which 

 has produced the deposit, it would be easy to refer the whole 

 to an alluvial origin, so characteristic are the undulating 

 lines of deposition, the alternation of coarse and fine mate- 

 rials inter stratified, including now large angular masses of 

 rock, and again graduating into the finest silt and mud. In 

 some places the lines of deposition are curved in regular un- 

 dulations, and in others they meet at a sharp unconformable 

 angle. Close observation alone detects that the whole ma- 

 terial is volcanic — pumice, scoria, sand, and fine dust, includ- 

 ing large blocks of inflated lava and tufa. 



It is impossible to see any diff*erence in the general cha- 

 racter of these deposits and of those which cover Pompeii, 

 only that the latter being mostly the result of one eruption 

 are less varied than the former, and more regularly stratified. 

 In both, the evidence of the aqueous action is very obvious ; 

 and we have historical as well as geological evidence of the 



VOL. LIT. NO. cm. — JANUARY 1852. K 



