from the Lipari Islands. 535 



ter more nearly allied to pitchstone-lava ; and in No. 23, it only 

 occupies a small portion of the mass, presenting a compact vitre- 

 ous texture, and a light ash-grey colour, exceedingly like a glass- 

 house slag. 



The next four are varieties of the compact pumice, which is 

 used on the island as a building-stone, a purpose for which, on 

 account of its lightness and freedom from humidity, it is peculiarly 

 well adapted. 



Nos. 24. and 25. are from the eastern side of the island ; the 

 latter being a portion of what some masons were excavating from 

 the foundation of a house for the construction of its walls. No. 26. 

 is much stratified, and was taken from Monte Gallina, at the 

 southern extremity of the island, as was also No. 27, though 

 greatly dissimilar in structure and appearance. 



Nos. 28. and 29. form embedded masses in the Pumice of 

 Campo Bianco, and were picked up along with the greater part of 

 the foregoing. They are evidently of volcanic origin, but that 

 they properly come under the denomination of " Pumice," admits 

 of some doubt. 



No. 30. is termed the lava of Monte Gallina. It has a some- 

 what pumaceous feel and appearance ; is much lighter and more 

 friable than most lavas ; is stratified in a singular manner ; and 

 contains numerous imbedded crystals of felspar. 



No. 3 1 . is another very peculiar rock, having little apparent re- 

 lation to any of the preceding ; evidently of volcanic origin, 

 however, and mottled with small cavities, which are coated with 

 silex. 



No. 32. On a small hill immediately above the town of Lipari, 

 there occur, imbedded in clay or decomposed tuff, considerable 

 masses of selenite, confusedly crystallized, stellated and fibrous, 

 of which this is a specimen. 



No. 33. Specular iro-ore, occurring in cavities upon Monte 

 Rosse, in which it has been sublimated by the action of heat. 



