340 Mr Forbes's Physical Notices of the Bay of Naples. 



doubt, as to its position in situ, but only on that account offers 

 the more curious field for inquiry. There are few strangers, 

 perhaps, who have visited Naples without seeing the elegant 

 snuff-boxes cut out of a substance termed there " lava d'lschia,"' 

 though probably a small number of them have thought of 

 examining its nature, or inquiring into its connection with 

 true lavas, and still fewer may have pursued their inquiry 

 upon the island itself. This substance, strange as it may ap- 

 pear, is nothing else than precious serpentine. Whether this 

 beautiful mineral, the undoubted concomitant of primitive 

 strata, be really indigenous to the volcanic mass of the island 

 of Ischia, is certainly a question worthy of inquiry. Yet though 

 it is so familiar a substance at Naples, I have been able to find 

 only one single allusion to its existence among the many stand- 

 ard and local works which I have consulted ; and I fear that 

 my own inquiries, though of some value, will not throw much 

 light upon the subject, as, at the period of my visit, I was un- 

 aware of the full interest of the inquiry. It is in Brocchi's 

 great work alone, upon the fossil conchology of the Subapennine 

 range that I find this substance noticed. " On the shores of 

 Ischia," says he, " are found fragments of this noble serpen- 

 tine, which are cut at Naples into snuff-boxes, but we are not 

 assured of its existence in the interior of the island ; I am not 

 sure but that these rolled masses may have been transported 

 by the sea, or left by vessels which had used them for bal- 

 last."* Various reasons induce me to differ from this able 

 Italian geologist, as far as ray means of information of the oc- 

 currence of serpentine in Ischia extend. These I shall 

 briefly state, without entering much into those hypotheses 

 which would assume importance, could the existence of ser- 

 pentine in Ischia as a locality be fully proved. 



In the first place, then, I myself met with this serpentine in 

 the interior of the island, in the bed of one of the small brooks 

 which run down the north side of Epomeo. I own, however, 



• I quote this important passage in the original : " Sulle spiaggie d'ls- 

 chia si trovano ciottoli di questa serpentina nobile che si lavorano in Nape- 

 li per fame tabacchiere ; ma essa non esiste per certo nel intorno dell iso- 

 la: ne so poi se quei massi rotolati sieno stati trasportati dal mare, o pure 

 depositati dai vasGclli che scrvissero di zavorra." — ConchioJogia Subapen- 

 nina. 4to. vol. i. p. 39. 



