66 Proceedings of Philosophical Societies. [July, 



its earthy base is converted from two to thirty feet deep into a 

 pitchstone-porphyry ; sometimes it becomes a pearlstone, at 

 others encloses a true obsidian. These rocks are connected 

 with a silicious trachyte, resembling in appearance the silicious 

 buhrstone of Paris. Resting on the semi-vitreous trachyte and 

 forming the base of the Montagna della Guardia, is a rock 300 

 feet thick, which the author distinguishes mineralogically from 

 common trachyte, and proposes to call greystone. 



In Jannone the trachyte overlies a limestone, which Brocchi 

 describes as transition limestone ; at the point of contact this 

 latter becomes dolomite. Having described the whole of this 

 group, the author terminates his paper by connecting their 

 geological structure with that of the neighbouring contineut of 

 Italy. 



A paper was read, entitled, " Notes accompanying Specimens 

 collected on a Journey through Part of Persia and the Russian 

 Tartaries ; " by James B. Fraser, Esq. MGS. 



June 4. — A paper was read, entitled, " Description accom- 

 panying a Collection of Specimens made on a Journey through 

 the Province of Khorosan in Persia;" by J. B. Fraser, Esq. 

 MGS. 



On quitting Teheran, the road passed by the roots of the 

 chain of Elburz, through the pass Gurdunee, Sirdara to Sem- 

 noon and Shahrood, over gravelly hills, having to the south a 

 salt desert, and appearances of salt on all sides ; thence by 

 Mey Omood, Abbassabad, Muzenoon, and Subzawar to Nisha- 

 pore, about 40 miles west of which place are found the cele- 

 brated torquoise mines, which are worked along the sides and 

 ridges of a narrow valley. The principal mine is called Abdool 

 Rezakee. The calaite is found pervading a soft yellow stone 

 and a mouldering reddish rock, as also a rock of much firmer 

 texture resembling quartz rock of a grey colour with reddish 

 streaks, and containing specular iron. A conglomerate rock 

 occurs in the vicinity. The mineral is found sometimes in veins, 

 sometimes mammillated in fissures, and at other times irregu- 

 larly dispersed through the rock. The author describes all the 

 mines actually worked ; they are the property of the crown, 

 and were valued, when Mr. Fraser visited them, at the annual 

 rent of 2000 tomauns of Khorosan, or about 3500/. sterling, 

 and are farmed to the highest bidder. At Derroad, 25 miles 

 from Nishapore, the primitive rocks of Elburz appeared similar 

 to those seen in the lofty range between Ispahan and Cashan. 



A paper was then read, entitled, " Geological Observations 

 on the Sea Cliffs at Hastings, with some Remarks on the Beds 

 immediately below the Chalk ;" by T. WebsteV, Esq. Sec. GS. 

 This paper commenced with a geographical description of the 

 cliffs on each side of the town of Hastings, from the White 

 Rock on the west to the end of Fairlee cliff on the east, which 



