No. I. — Account of Mount Vesuvius. 209 



other zeolites, the cubizite or analcime, and the rnesotype, oc- 

 cur in the lavas of Monte Somma. 



The genus Felspar is amazingly varied in Mount Vesuvius, 

 and many varieties are peculiar to it. I must merely confine 

 myself to mentioning their names, as far as the latest dis- 

 coveries have separated them. The rhomboidal felspar or 

 nepheline is nearly limited to cavities in the granular limestone 

 of Monte Somma, as are the Meionite and Sommite. Albite is 

 a species of felspar which appears to be known under two other 

 names, Cleavelandite and Christianite. See this Journal, 

 No. xiv. p. 32(3. The last name is the one given by Messrs 

 Covelli and Monticelli in honour of Prince Christian of Den- 

 mark. Icespar is an abundant production of Vesuvius, and anor- 

 thite is peculiar to it. See the Appendix to Molls' 1 Mineralogy. 

 The genus Augite occurs in great abundance, and in very va- 

 rious forms which it would be tedious, were I competent, to par- 

 ticularize. One beautiful white variety is found in the Fossa 

 Grande. I must, however, pause to observe that beautiful and 

 well characterized specimens of hornblende are found in Vesu- 

 vius ; although Humboldt, in his Account of the Canary Is- 

 lands, says, " Hornblende is extremely rare at Teneriffe ; and 

 I never found it in the lavas of Vesuvius. Those of Etna 

 alone contain it in abundance."" I have several Vesuvian spe- 

 cimens in my possession. Tremolite not only occurs in the 

 calcareous rocks of the Somma, but also in lava. My speci- 

 men is from that of 1809 ; it is highly crystalline and splendent. 

 Epidote or pistacite is the next important mineral of the genus 

 augite which occurs in Vesuvius. It is green and crystallized 

 upon the limestone in rhomboidal prisms. There is, however, 

 another variety of epidote, the scorza of some mineralogists, 

 the scorsalito of the Neapolitans, which is arenaceous epidote. 

 All the specimens in my possession are of the eruption of 1822; 

 the colour pale reddish-brown, and the surface uneven and 

 shining from minute crystals. Examined with the microscope, 

 they have a beautiful appearance, and are found intermixed 

 with Breislakite, — a mineral whose characters are quite un- 

 determined, — which occurs in acicular crystals of a red colour. 

 Of the genus azure spar the lazulite or lapis lazuli has been 

 discovered among the ejected minerals of Vesuvius. It is 



