TRANSACTIONS OF SECTION C. GGo 



The author siigfrests — 



1. That tlie gravels are river gfavela formed since the country last rose above 

 the sea ; 



2. That the process of elevation was not continuous, hut that short periotls of 

 rapid movement were separated by long periods of repose ; 



3. That the gravel-flats are the work of the rivers during the periods of 

 repose ; 



4. That the earth-movements did not afl'ect the whole area uniformly, and that 

 local depressions occurred. 



In support of these conclusions the author refers to the step-terraces so common 

 in the fjords and to the old coast-plain and shore-lines which occur above and 

 below the present sea-level on the Norwegian coast. 



As evidence of local depression, he refers to the deep channel of Drift in the 

 valley of the Cam, described by Mr. W. AVhitaker,' and to the great thickness of 

 the Corbicula Jtuminalis bed at Crayford. 



G. On the Occurrence of Dionte associated with (rranite at Assotcail, 

 Upper Eyijpt. By Alexander Somervail. 



Immediately below the front of the Cataract Hotel there ia exposed an 

 interesting section of the reddish granite of the neighbourhood. It is notable for 

 a mass of dark diorite, which seems to cut it as a vein or dyke, running in an 

 E.N.E. and W.S.W. direction. 



The breadth of this dyke-like mass is variable, but on an average it is about 

 three feet Avide. 



The walls of both are as a rule sharply defined, without any apparent passage 

 of the one into the other, although at some portions of the margin of the diorite 

 there are a few red crystals of the felspar of the bounding granite. 



There are, however, about the central portion of the diorite, crossing it at 

 right angles, two small veins of the reddish granite of the parent mass. One of 

 these is only about quarter of an inch wide, and the other about two inches in 

 width. 



These two veins are both in colour, and also in composition, exactl)- the same 

 as the mother rock ; and are not continued into the parent mass as distinct veins, 

 but are essentially a part of the granite itself. 



The author did not enter upon any theory of explanation, but it is, he tliinks, 

 obvious that the granite and diorite are not separated from each other by any 

 great diti'erence of age. 



7. Kote on some Ilornhlende Porphyrites of Victoria (Australia). 

 By James Stirling, Government Geologist of Victoria. 



The existence of auriferous quartz veins associated with a class of eruptive' 

 rocks, which are intrusive to the Upper Silurian formation (shales, sandstones, 

 conglomerates, and limestones) of Victoria has long been known. The frequent 

 occurrence of hornblende in this class of rock has led to the use of the term 

 diorite for most of the dykes, although marked differences in mineral composi- 

 tion and structure were frequently observed. During a recent geological and 

 underground survey of the Walhalla Goldtield, where the dykes were classed as 

 diorites, 1 caused a number of samples of the dykes to be selected and sliced for 

 petrographic investigation, with the result that many of the intrusive rocks were' 

 found to belong to several diiierent classes, in which hornblende was either 

 wholly absent or but sparingly represented, being replaced by mica-forming mica- 

 feloites, ifcc. This iaquiry led to a closer examination of the well-knowu Wood's- 



Quart. Journ, Geol. Soc, vol. xlvi. p. 333. 



xx; 



