Mode of Transport of Granite and other Rocks. 443 



Throughout India, wherever there is deficient subsoil-drainage 

 or excessive evaporation and limited rainfall, salts are apparent 

 either in supersaturated subsoil-solutions or as crystallizations in 

 the soil. They are most abundant in basaltic regions, and in a 

 lake occupying a hollow in the basalt in Berar carbonate of soda is 

 deposited in abundance from the water, which becomes super- 

 saturated during the summer. 



The author commented on the efficacy of such a liquid as a solvent 

 of silica, and noticed the selective action of the agent which had 

 affected the Soudan pebbles and had corroded some layers more than 

 others ; he suggested that while this might be to some extent due 

 to differences in composition, it was more probably owing to differ- 

 ences of nodular constitution. He considered it unnecessary to refer 

 to the action of humic acid, because, while the salt to which the 

 solvent action is attributed would be capable of doing such work, 

 and would be probably abundant in the region referred to, we could 

 not expect any great amount of humic acid in the same area. 



2. " On the Probable Mode of Transport of the Fragments of 

 Granite and other Bocks which are found imbedded in the Carboni- 

 ferous Limestone of the neighbourhood of Dublin." By Prof. V. 

 Ball, Esq., M.A., F.B.S., F.G.S. 



Angular fragments of granite and of schist, quartzite, and vein- 

 quartz, such as might have been derived from the metamorphosed 

 rocks which rest on the granite near Dublin, have been discovered 

 in beds of Carboniferous Limestone, which often contain fragments 

 of fossils, especially Encrinites. They have been previously noticed 

 by Professor Haughton, Mr. H. B. S. Montgomery, Prof. Jukes, and 

 Mr. Croll. While Prof. Jukes refers their transportation to the 

 agency of land-plants, Mr. Croll quotes their occurrence in support 

 of his argument as to the existence of glacial conditions during the 

 Carboniferous period. 



The author observed that the specimens exhibited none of the 

 indications of the existence of glacial conditions whether we regard 

 the characters of the boulders or the nature of the rock in which 

 they are imbedded, which contains no such silt as that occurring in 

 the boulder-bed of the Talchir formation. Whilst rejecting the 

 view that they were transported by ice, he pointed out that they 

 need not necessarily have been carried by land-plants, but that they 

 might have been torn from the sea-floor by marine algae, some of 

 which v may have had a more buoyant character than those of modern 

 seas. He cited the case of a sandy beach in the neighbourhood of 

 Youghal, which is strewn with limestone fragments, which had 

 been conveyed by sea-weeds thrown up after storms from submarine 

 banks. 



It was suggested that the occurrence of natural fissures in the 

 rocks and cracks produced bj" concussions from large masses hurled 

 about by the waves might sufficiently explain how the fragments 

 could be freed from the main mass of the reefs under the stress of 

 the waves. 



