ON ITS EXTERIOR. VOLCANOES. 303 



by them. In the hornitos there is nothing resembling a 

 crater; and they consist (which is an important cha- 

 racter) of mere basaltic balls of concentric separable 

 shells, without any intermission of loose angular scoriae. 

 At the foot of Vesuvius, at the great eruption of 1794 

 (as also at earlier epochs), there were formed, arranged 

 over a longitudinal fissure, eight different little craters 

 of eruption, " bocche nuove," the so-called "parasitic" 

 eruption-cones, pouring forth lava, which would of it- 

 self distinguish them altogether from the Jorullo hor- 

 nitos. "Your hornitos," wrote Leopold von Buch to 

 me, "are not cones heaped up by the fall of erupted 

 substances ; they have been upheaved directly from the 

 interior of the earth." The same great geologist com- 

 pares the origin of the volcano of Jorullo itself to that 

 of the Monte Nuovo in the Phlegraean Fields. The 

 same view, in respect to the elevation of the six volcanic 

 mounts, impressed itself, as the most probable one (see 

 above, pp. 292, 293), on Colonel Riano and Commissary 

 Fischer in 1789, on myself, at first sight, in 1803, and 

 on Oberbergrath Burkart in 1827. In regard to both 

 the "new mountains" (Monte Nuovo and Jorullo), 

 which arose in 1538 and 1759, the same questions 

 presented themselves. Respecting the Italian Mount, 

 fuller accounts have been collected nearer to the time 

 of the catastrophe, and derived from more qualified 

 observers, by Falconi, Pietro Griacomo di Toledo, 

 Francesco del Nero, and Porzio. One of these (the 

 most learned), the celebrated Porzio, says, "Magnus 

 terrse tractus, qui inter radices montis, quern Barbarum 

 incolse appellant, et mare juxta Avernum jacet, sese 

 erigere videbatur et mentis subito nascentis figurarn 



