24 GEOLOGICAL MEMOIRS. 



to reproduce the interferential colours of mother-of-pearl, of Barton's 

 " Iris-button," &c. By covering the etched surfaces with a thin 

 layer of isinglass, he obtains impressions fit for microscopical exami- 

 nation, both by transmitted and by reflected light. Similar impres- 

 sions taken on the etched surfaces of arragonite, iron-pyrites, and 

 other minerals were also exhibited. [Count Marschall.] 



On Tertiary Fossils /rom Belgrade. By Dr. M. Hornes. 



[Proceedings of the Imp. Geol. Instit. Vienna, December 12, 1854.] 



A SUITE of fossils and rock-specimens forwarded by Prof. Pancic 

 from the environs of Belgrade were found by M. Hornes to agree 

 with the organic remains and mineral deposits of the Vienna basin. 

 M. Hornes thinks the arenaceous clays near Radowitza, south of 

 Belgrade, to be equivalent to the tertiary strata of Baden near 

 Vienna, or to those of Lapugy in Transylvania. The deposits of 

 Tasmajdan, Knezevac, and Vischnitza were regarded as belonging to 

 the Leitha-limestone ; and those of Mokrilug and Belaboga, together 

 with the hill on which the fortress of Belgrade is built, were referred 

 to the Cerithium-beds. 



Notwithstanding the geological information on the environs of 

 Belgrade resulting from the researches of MM. Boue and Viquesnel, 

 a more complete knowledge of the probably abundant fossil fauna of 

 the district is highly desirable. The late M. Fuchs forwarded to 

 M. Partsch a drawing of a Caprina, which goes to confirm M. 

 Viquesnel' s statement that Belgrade is situated at the foot of a 

 cretaceous range surrounded by tertiary deposits. 



[Count Marschall.] 



On Clinochlore and Mica. By Col. N. von Kokscharov. 



[M. Haidinger's Report, Imp. Geol. Instit. Vienna, November 7, 1854.] 



The name " Clinochlore" has been given by Mr. Blake to a mineral 

 species from Westchester, Pennsylvania, which exhibits two optical 

 axes. Lieut. -Col. Kokscharov, by carefully measuring the angles of 

 the crystals in the a ariety from Achmatowsk (Ripidolite of Kobell, 

 Chlorite of G. Rose), found these angles in concordance with the 

 optical phsenomena observed in this mineral. 



M. Kokscharov also, by exactly measuring the angles of complete 

 crystals of Mica, brought from Mount Vesuvius by M. Abich, has 

 proved their forms to belong really to the Orthotypic System (as 

 M. de Senarmont had supposed), although they bear the character 

 of Macrodomous Orthotypes generally occurring among augitic 

 crystals. [Count Marschall.] 



