Letter to Sir Charles Lyell from Carlo Gemmellaro answering a list of questions that Lyell had evidently posed to him in a previous letter. Topics covered include volcanic strata, inaccuracies in maps of the area around Mount Etna drawn by Wolfgang Sartorius Von Waltershausen, and Lyell's theory that the 2 craters of Mount Etna were contemporary. Gemmellaro disputes this theory as each crater ejected different types of rock, Felspatic and Pyroxenic, with no mixing of the two. Gemmellaro suggests that one crater was that of ancient Etna and the second is more modern, 10 February 1858.