Minutes of Proceedings. ix 



The abstract of a communication of Professor E. H. L. Schwarz 



on " Solifluction " was read. 



Solifluction is a term coined by Andersson for the flow of saturated 

 soil down mountain sides. Originally used only for regions covered 

 with ice and snow, the object of the present paper is to show that 

 the same action goes on in temperate countries, only to a smaller 

 extent, producing stone courses in the mountainous districts, and a 

 gradual downward creep of soil and sub-soil in parts of the country 

 which have less relief. Under the same term must be included the 

 flows of volcanic ashes saturated with water, which are characteristic 

 of the so-called mud-volcanoes in South America, Java, &c. In 

 former periods solifluction is shown to have been operative from the 

 occurrence of breccias and conglomerates formed of materials which 

 have not been sorted into grades by flowing water. In some cases, 

 as in the Dwyka conglomerate, these can be explained by ice-action, 

 but in others, where ice as an agent must be ruled out, the pheno- 

 menon of boulders of all sizes intermingled in a conglomerate can 

 be explained by solifluction. The principle involved is that, when 

 the Kernel formation of soil is destroyed by heat and the sand grains 

 fall apart, or in loose sand, where the particles are 3 mm. or less in 

 diameter, the interspaces are capillary in size, and water contained 

 in these pores is held up and will not drain away. The mass thus 

 permeated with water becomes a semi-liquid of high specific gravity; 

 it will flow if on a slope, and carry with it, regardless of size, large 

 boulders whose specific gravity is only a little more than that of the 

 mud. 



Ordinary Monthly Meeting. 

 Wednesday, May 1, 1907. 

 Dr. J. C. Beattie, President, in the Chair. 



Dr. L. GouGH, Mr. A. J. Louw, Miss H. M. L. Kensit, and Mr. II. 

 Neethling were duly elected Ordinary Members. 



Nomination. — The Kev. J. H. Whaits, by M. Wilman and Dr. 

 J. C. Beattie. 



Dr. Marloth exhibited some specimens of rocks and plants 

 recently brought from Tristan d'Acunha by Mr. P. Keytel. The 

 rocks were all of igneous origin, some having been taken from the 

 beach and some from the summit of the peak, which is 7,800 feet 

 high. The latter consists entirely of scoriae, which were as light as 

 pumice stone. With regard to the plants. Dr. Marloth said, in 

 a few introductory remarks, that the vegetation of the island was 



