Mr. Ibbetson on the Origin of veins of Gold in Quarts. 73 



coating all the inner surfaces with tufa. 3. The shell was dissolved 

 and removed before the consolidation of the surrounding mud, which 

 thus obtained access to all those cavities whose calcareous lining was 

 incomplete. 4. The cavities which the mud could not enter were 

 filled, or nearly filled with crystalline carbonate of lime. Mr. Wood- 

 ward concluded his paper with remarks on the structure and filling 

 up of the siphuncle in Actinoceras and other allied forms of 

 Cephalopoda. 



5. " On Trap-dykes intersecting Syenite in the Malvern Hills, 

 Worcestershire/* By the Rev. W. S. Symonds, F.G.S. 



The author described the dykes of greenstone and trap traversing 

 syenite in a quarry between the Winds Point and the Obelisk. 

 The syenite is altered by contact with the dykes, and the appear- 

 ances closely resemble those observed by the author in the syenite 

 on which the great bonfire was made on the Beacon Hill in January 

 last. 



6. "On the Movement of Land in the South Sea Islands." By 

 James G. Sawkins, Esq., F.G.S. 



The author when visiting the Friendly Islands in 1 854 collected 

 information relative to an earthquake which had lately occurred, 

 accompanied by a sinking of the eastern and north-eastern portion 

 of Tongataboo, and an uprise on the western coast, and the appear- 

 ance of an island or shoal of black sand at a distance of thirty miles 

 to the westward. Another earthquake occurred afterwards at Nina- 

 poon, an island to the northward, which was not felt at Tongataboo. 

 The author also referred to other indications of local movements of 

 land in the Pacific Islands. 



7. "On the possible origin of veins of Gold in Quartz and other 

 rocks." By L. L. B. Ibbetson, Esq., F.R.S., F.G.S. 



Having mixed a solution of gold in nitromuriatic acid with five 

 times its weight of water, and placed it in a Berlin evaporating dish 

 on a thick sheet of copper over a gas-lamp, the author observed a 

 crack in the basin, which was increasing. On transferring the solu- 

 tion to another basin, he found that the crack presented a vein of 

 gold ; the pure gold forming small nodular masses along the 

 fissure, both inside and out, and resembling veins of gold in auri- 

 ferous quartz-rocks. Under the circumstances of the low tempera- 

 ture at which the solution was being evaporated, the diluted state 

 of the solution still left unevaporated, and the diflference of the 

 appearance of the nodular form of the gold- vein from the usual ap- 

 pearance of the metallic gold obtained by evaporation from such a 

 solution, the author thought it worth while to describe and exhibit 

 the specimen to the meeting. 



