126 Geological Society : — 



belong to different epochs, but include some rocks (sucb as the 

 gneiss) resembling Archaean. These seem to mark an eastward 

 extension of the anticlinal axis previously traced by Capt. Lyons to 

 Wady Haifa in the Nile Valley from the west. 



Miss Aston gives two tables, one of which shows the actual 

 amounts of substances found in the wells of Murrat, Bir Tilat Abda, 

 and Bir Ab Anaga, while the second shows their approximate 

 constitution. 



2. ' On the Origin of some of the Gneisses of Anglesey.' By 

 Charles Callaway, M.A., D.Sc, E.G.S. 



The author still maintains the occurrence of two pre-Cambrian 

 groups in Anglesey, the later of Pebidian age. In the present 

 paper a description is given of the production of gneissic structure 

 in rocks of the earlier group occurring in the south of the 

 island. The products of metamorphism are similar to those described 

 by the author in the Malvern area, (i) Simple schists, granite is 

 converted into mica- gneiss, diorite into hornblendic or chloritie 

 gneiss, and felsite into mica-schist ; (ii) Injection-schists. In 

 Anglesey felsite plays the part which is taken by granite at Malvern, 

 and certain important differences arise. Gneiss of primary injection 

 is formed by the parallel veining of felsite and diorite, and the 

 author describes cases ; he also notices the occurrence of meta- 

 morphosed diorite-blocks in grey gneiss, which afford evidence of 

 its eruptive origin. Gneiss of secondary injection is well seen in 

 the Llangaffo cutting, and is explained in a manner similar to that 

 given for an infiltration -gneiss at Malvern, felsite being substituted 

 for granite. The infiltration-products are mainly chlorite, iron 

 oxide and epidote, and out of the chlorite and iron oxide, with 

 the addition of materials from the felsite, black mica has sometimes 

 been constructed. The changes have occurred along planes of dis- 

 continuity formed subsequently to the consolidation of the rocks. 



May 12th.— Dr. Henry Hicks, F.R.S., President, in the Chair. 

 The following communications were read : — 

 1. ' On the Gravels and associated Deposits at Newbury (Berks).' 

 By E. Percy Richards, Esq., F.G.S. 



After a general sketch of the geology of the Valley of the Kennet, 

 the superficial deposits at and in the neighbourhood of Newbury 

 are described in detail, from observations made by the author during 

 the progress of the main drain age- works in 1894. 



The author classifies the strata which he has examined in five 

 groups : — 



1. The Preglacial Southern Drift. 



2. The Glacial Drift (Donnington). 



3. The Upper River-gravel. 



4. The Lower River- gravel. 



5. The Neolithic peat-becls (shell-marl, peat, and loam). 



1. The first of this series is the flint-gravel constituting the 



