232 



Reviews — Geology of Windsor and Chertsey. 



and syenite, with olivine nionchiquite and ulrichite containing the 

 brown hornblende, barkevikite. 



Summary. — The geological succession in Korth- Western Angola is- 

 as follows, rocks of doubtful position being placed on the right : — 



Tertiary 



Cretaceous 



Karroo (?) 



Paleozoic 

 Silurian (?) 



Archaean 

 Complex 



Eecent Deposits. 



fMiocene 

 \Eocene 



Cenomanian. 



(Bed Conglomerate 

 Grey Grits 

 Carbonaceous Beds 



f Dolomite and Limestone Series. 

 VBembizi Beds. 



j'Granulitic Albite Granites. 



-[ Gneisses and Gneissose Granites. 



Schists and Crystalline Limestones. 

 (To be continued in the June Number.) 



Alkaline igneous rocks. 

 Irritative contact* 



Diabase Intrusions. 



Irruptive contact. 

 Irruptive contact* 



ZRIE^rilE-V^S. 



Memoirs of the Geological Survey of England and Wales. 

 The Geology of the Country around Windsor and Chertsey. By 



Henry Dewey, F.G.S., and C. E. N. Bromehead, B.A., F.G.S. 



pp. i-vi, 1-123. 1915. Price 2s. 6d. 

 T PHIS memoir is an explanation of Sheet 269 of the 1 inch Geological 

 L Map. Pressure of work due to the War has, however, delayed 

 the colour-printing of the map, and it is not yet ready for publication, 

 but the authors give a sketch-map of the area on the scale of 4 miles 

 to the inch. (p. 2.) 



The sketch-map shows that the district is divided into three nearly 

 equal parts: (1) mainly London Clay in the centre and west; 

 (2) Bagshot Sand in the south ; and (3) river gravels and brickearth 

 on the north-eastern side of the area. 



In the first of these parts the London Clay occupies a large tract, 

 Windsor Park and much of Windsor Forest being upon it, and it also 

 extends underground over almost all the rest of the district. Its 

 thickness is about 400 feet in the east and rather less than 300 feet 

 in the west. The Basement-bed with Ditrupa and shells is noted in 

 several places and appears to be continuous. Fossils are not 

 uncommon, and the authors give a list of considerable interest from 

 near the top of the formation at Bracknell. There is a small 

 exposure of Reading Beds in the north-western corner of the area, and 

 they have been pierced in well-sections elsewhere. The thickness 

 varies from about 100 feet in the south to 60 feet in the north. 

 Chalk is found at the surface in the north-eastern corner of the district 



