Notices of Memoirs — British Association. 413 



■across. There is apparently no stratification, and the mode of 

 occurrence seems to mark this as a small volcanic vent. 



10. North of Mynydd anelwog. — (Annelog). The low crag near 

 the spring consists of an ash, finer than, but of very similar 

 materials to, the agglomerate just described. Fragments of andesite 

 or basalt are almost identical with the constituents of the preceding 

 specimen, and those of green viridite might be derived from the 

 same source, while occasionally a piece of scoria occurs. The 

 fragments as seen by microscopic examination are small, with 

 slightly irregular outline, and separated by strings of fine dust. 



Thus all the patches of " serpentine," except the two mentioned, 

 have now been examined, with the result that not only is there no 

 serpentine present but there is no uniformity in their character, and 

 I shall be able to show that similar rocks occur at many other places 

 in the neighbourhood. Sometimes these " serpentines " are dolerites 

 or compact diabases (andesites or basalts) ; sometimes they are true 

 volcanic agglomerates. Although, in many cases, they are not 

 interbedded, some probably represent lava flows, or an ash of 

 transported fragments. This result, therefore, further illustrates 

 the characters, which were first described by Professor Bonney from 

 Forth din lleyn. His paper thus gave the key-note to the under- 

 standing, not only of that locality, but of others. The question of 

 the geological age of these masses can only be discussed in 

 connection with the surrounding district, since it affords additional 

 examples of similar and allied rocks. 



isroTiOES OIF nvLEH^viroiias. 



I. — British Association for the Advancement of Science. Sixty- 

 second Meeting, Edinburgh, August 3rd, 1892. Fresident, Sir 

 Archibald Geikie, LL.D., D.Sc, For. Sec. E.S., F.R.S.E., 

 F.G.S., Director-General of the Geological Survey of the United 

 Kingdom. 



Titles of Papers Read in Section (C), Geology, August 4-10. 

 Professor C. Lapwoeth, LL.D., F.E.S., P.G.S., President of Section. 



The President's Address. 



0. W. Jeffs. — Report of the Committee on Geological Photographs. 



J. Lomas. — On the Glacial Distribution of the Riebeckite-Eurite of 



Ailsa Craig. 

 Dr. H. W. CrossTceT/. — Report of the Committee on Erratic Blocks. 

 J. W. Gray and P. F. Kendall. — The Cause of the Ice Age. 

 W. A. E. tfssJier. — The Granites of Devon and Cornwall. 

 Dr. A. Irving. — The Malvern Crystallines. 



J. G. Goodchild. — The St. Bees Sandstone and its Associated Rocks. 

 K. Woods. — The Igneous Rocks in the Neighbourhood of Builth. 

 A. G. C. Cameron. — Note on a Green Sand in the Lower Greensand, 



and on a Green Sandstone in Bedfordshire. 

 A. G. C. Cameron — The Fuller's Earth Mining Company at Woburn 



Sands. 



