210 PETEOIOGY. 



by rapid cooling, the rock in the vein assumed a porphyritic struc- 

 ture. The crystalline texture of the granite is lost; the further the 

 vein is from the main mass the more decided is the porphyritic struc- 

 ture. The texture of the vein is more compact towards the walls. A 

 description of microscopic structure of the " salband" is given. 



F. W. B. 



Malaise, C. Sur quelques roches porphyriques de Belgique. [Por- 

 phyritic rocks of Belgium.] Bull. Ac. roy. Belg. 2 ser. t. xxxviii. 

 no. 7, pp. 70-87. 



The porphyritic rocks of Belgium, which are looked upon as plutonic 

 or metamorphic, are found in the Stavelot hills and in those of Brabant 

 and Sambre-et-Meuse. One eurite alone has been observed in the 

 Lower Devonian, at Piroy (Malonne). "With the exception of the last 

 case, these rocks, although later than the Cambro- Silurian series, are 

 pre-Devonian. The author brings together in this paper all the ob- 

 servations of previous writers, besides his own, regarding these rocks. 

 He divides them into simple and compound felspathic rocks, eurite 

 alone belonging to the former group, whereas the latter comprises 

 hypersthenite, chlorophyre, diorite, and the schistoid porphyries, which 

 themselves comprise the schistoid porphyry, the dlhite ^liylladiftre, and 

 the eurite ^hylladifire of Dumont. G. A. L. 



. Eapport sur un memoire en reponse a la question: Paire 



connaitre, notamment au point de vue de leur composition, les 



roches plutoniennes, ou considerees comme telles, de la Belgique 



et de I'Ardenne frangaise." [Report on a paper on the plutonic 



rocks, or those regarded as such, of Belgium and of French 



Ardenne.] Bull. Ac. Roy. Belg. 2 ser. t. xxxviii. no. 12, pp. 775- 



784. 



The report proper is prefaced by a short resumi of the rocks which, 



in the author's opinion, should form the subject of study, in order that 



the question asked may be properly answered. This introduction 



forms a summary of Dumont's views respecting the plutonic rocks of 



Belgium and the adjoining part of Prance. G. A. L. 



Malet, H. p. "What is Basalt ? Science Gossip, no. 114. 

 Note on the occurrence of apatite and olivine in basalt, as proof that 

 the rock is not igneous. 



Maskelyne, Prof. N. S., and Dr. "W. Plight. On the Character of 



the Diamantiferous Eock of South Africa. Quart. Journ. Geol. 



Soc. vol. XXX. pp. 406-416, woodcut. 



The diamonds occur in an altered igneous rock, apparently a bron- 



zite-rock, converted, for the most part, into a hydrated magnesium 



silicate. The soft ground-mass of the rock contains included fragments 



of shale and a new mineral of the vermiculite group, described as 



Yaalite. It also contains a green ferriferous enstatite (bronzite), a 



paler- coloured bronzite, a hornblendic mineral resembling smaragdite, 



