Minutes of Proceedings. xxi 



Ordinary Monthly Meeting. 

 March 2, 1904. 

 Dr. J. D. F. Gilchrist, President, in the Chair. 



Dr. E. Sinclair Stevenson was elected ordinary member. 



Messrs. H. B. Brown and D. J. Haarhoff were nominated as 

 ordinary members by J. E. Sutton and L. Peringuey. 



Dr. Gilchrist exhibited a cluster of fish eggs attached to a 

 piece of "red bait" (a large ascidian) from False Bay. They were 

 small beings, a little less than 1 millimeter in diameter. A few oil 

 globules occurred in the yolk mass which were of a dull yellowish 

 colour. The embryos were fairly well advanced when procured, and 

 some of them had hatched out. They were thought to belong in all 

 probability to a species of blenny, probably Blennius comutus, which 

 occurs in False Bay. This is the third kind of demersal fish egg 

 found in Cape waters, one of the other two has now been found to 

 be that of a species of Lepidog aster, hitherto unrecorded. 



Mr. A. W. Eogers read a paper written in collaboration with Mr. 

 A. L. du Toit on "The Sutherland Volcanic Pipes and their relation 

 to other vents in South Africa." 



In the Sutherland Division there are 30 volcanic pipes filled with 

 materials of various kinds. They occur on the Commonage west of 

 the village, at Matjesfontein, Silver Dam, Saltpetre Kop, Blaauw 

 Blommetjes Keep, De Vrede, and Portugal's Eiver. They can be 

 divided into three classes : — 



1. Those filled by melilite-basalt or glassy lava. (Commonage.) 



2. Those filled partly by melilite-basalt or glassy lava and partly 

 by tuff. (Commonage and Matjesfontein.) 



3. Those filled with breccias. (Silver Dam, Saltpetre Kop, Blaauw 

 Blommetjes Keep, De Vrede, and Portugal's Eiver.) 



All these pipes pierce the Beaufort beds which are slightly up- 

 turned at the contact with the pipes. In the case of the large vent 

 of the Saltpetre Kop group the strata dip away from it on all sides, 

 at first steeply (50°-90°), but they become horizontal at a distance of 

 rather over a mile. The melilite-basalts are composed of olivine, 

 melilite, biotite, augite, perofskite, ilmenite, and a devitrified base 

 containing serpentine and calcite. Some outcrops are much altered, 

 but at more than one the component minerals are remarkably fresh. 

 They show a general resemblance to the melilite-basalt of Spiegel 

 Eiver, which is also described in the paper, and of which a complete 

 chemical analysis by Mr. J. Lewis of the Government Laboratory is 



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