PETROLOGY. 213 



of Coticule, &c.] Reports by MM. de Koninck and Malaise on the 



above paper. Bull. Ac. R. Btly. ser. 2, t. xlii. nos. 9, 10. 



Gives a sketch of the author's views of this rock, which is used for 



whetstones. It contains a micaceous mineral allied to damourite, 



garnet, tourmaline, and many other microliths. T. G. B. 



Renard, A. Some Results of a Microscopical Study of the Belgian 

 Plutonic Rocks. Micr. Journ. vol. xv. pp. 212-218 ; plate. 



Attention is paid more especially to the fluid-cavities and their con- 

 tents, with a view to the determination of the temperature and pressure 

 under which the rocks were formed. E. T. N. 



Rodriguez, F. d. y. [Ophite of Pando, in Santander.] Ann. Soc. 



Espah. Hist. JSat. 

 The rock, of supposed Triassic age, contains a mineral intermediate 

 between augite and diallage. C. E. D. 



Roemer, Ferd. Ueber ein Yorkommen von Blitzrohren oder Ful- 



guriten bei Starczynow unweit Olkusz im Konigreiche Polen. 



[Occurrence of Fulgurites at Starczynow, near Olkusz, Poland.] 



ja. Jahrh. Heft i. pp. 33-40, woodcut. 



In a broad waste of sand S.W. of Olkusz many fulgurites were found ; 



the relative positions of 24 are marked on a plan. The tubes vary in 



shape, their sections being round, angular, or compressed laterally. 



In those tubes w^hich are about the thickness of the finger the walls 



are only from 1 to 2 mm. thick ; in larger tubes the walls are thicker. 



The longest tube which has been dug out of the sand measures 2*19 



metres. The sand is the common white quartzose sand of the N. 



German diluvial plain. The tubes may have been formed by lightning 



at very difi'erent dates, as the vitreous material of their walls w^ould 



not be readily altered. F. W. R. 



Rosenhusch, H. Einige Mittheilungen iiber Zusammensetzung und 

 Structur granitischer Gesteine. [Structure of Granitic Rocks.] 

 Zeitsch. deutsch. geol. Ges. Bd. xxviii. Heft 2, pp. 369-390. 



Classes granites under : — 1. Muscovite granite ; 2. Granitite, where 

 the mica is biotite ; 3. Hornblende-granite, where there is hornblende 

 instead of mica ; 4. Granite proper, with potash- and magnesia-mica ; 

 5. Hornblendic granitite, with hornblende and biotite. Notes the pre- 

 sence of augite in granitite-dykes and in granite-porphyry veins, aschaf- 

 fite, &c., but not in Muscovite granite. Adopts Vogelsang's name of 

 " Granophyre " for rocks intermediate between granite and quartz- por- 

 phyry, a complete passage being found between the two ; such occur 

 in veins chiefly ; the microscopic appearance is described and examples 

 given. E. B. T. 



Roth, J. Ueber eine neue Berechnung der Quantitaten der Gemeng- 

 theile in den Vcsuvlaveu. Zeitsch. deutsch. geol. Ges. Bd. xxviii. 

 Heft 3, pp. 439-444. 



Note on Prof. Haughton's calculations of the proportions of consti- 



I 



