PETROLOGY. 215 



'No. 4. On Ingenite Rocks. Deals with an intrusive mass of granitic 

 rock (elvanyte) at Longstone, Tipperary. Microscopical examination 

 shows it to consist of a felspathic base, containing crystals of yellowish- 

 green felspar, small blebs of quartz, and some mica. Figures are given 

 showing the microscopic characteristics. E. T. H. 



Kinahan, G. H. Granitic and other Ingenite Rocks of Yar Con- 

 naught, and the Lower Owle ; or the mountainous tract of country 

 west of Loughs Mark and Corrib. Proc. K. Irish Acad. ser. 2, 

 vol. ii. (Science), no. 2, pp. 102-138, plates 9-12. 

 Part 1 refers to the different descriptions of rock, Plutonic, Meta- 

 morphic, and Granitic, with their occurrence, modifications, and 

 gradations. Part 2 is occupied with suggestions as to the origin of 

 the granitic and other Hypogene rocks. The non-intrusive hypogene 

 rocks were formed from pre-existing rocks by heat, the granitic rocks 

 having been more or less fused and liquified, others (as gneiss, &c.) 

 being never fused or liquified, but changed by heat, in this case pro- 

 bably wet. The intrusive groups were probably the result of parts of 

 underlying fluid magmas, either acid or basic, being forced into cracks 

 and fissures by the weight of the overlying mass. The author con- 

 siders granite mostly the result, not the cause, of metamorphism. E. T. H. 



. Sedimentary Basalt (Doleryte). Sci. Goss. no. 132, p. 279. 



Notes thin-bedded Antrim dolerytes, which may be metamorphosed tuff?. 



Kocli, Dr. G. A. Geologische Mittheilungen aus der Oetzthaler 

 Gruppe. [The Oetzthal Mts., «S:c.] Jahrh. k.-Jc. geol. Reiclis. 

 Bd. XXX. Heft 3, pp. 247-258. See also Verh. Tc.-h. yeol. lieiclis. 

 pp. 123, 124. 



Describes the rocks of the Pitzthal and Kaunserthal, mostly gneiss 

 and crystalline schists. Notes on the minerals will follow. 



Lang, H. 0. Ueber die Absonderung des Kalkstein von Elliehausen 



bei Gottingen. [Structure of Limestone.] Zeitsch. deutsch. geol. 



Ges. Heft iv. pp. 842-853, with plate. 



Describes the prismatic structure of certain limestones of the Cera- 



<?*<f?-beds of Elliehausen, near Gottingen, and refers it to the effects of 



great lateral pressure. F. W. R. 



^ . Parallclfaserung und Siiulen- Absonderung. Mikrostructur- 



Studie. [Fibrous and Columnar Structures.] Jahresluft Ver, 

 Nat. Wiirtt. Bd. xxxi. p. 33G, plate. Abstract in N. Jahrh. 

 Gives the results of microscopic studies of certain minerals with 

 fibrous structure, such as gypsum, and of prismatic basalt, undertaken 

 with the view of determining whether the structure was due to increase 

 of volume. Finds that this ex])lanation holds only in certain cases, 

 and concludes that the parallel fibres and the prismatic forms aro 

 generally the result of lateral compression during the formation of the 

 substance. F. W. R. 



