On the Valley- Gravels about Reading. 281 



bearing rocks of South Africa, and considers that the conditions 

 under which the plumbago was formed in the Lake District 

 approached much more closely to those which gave rise to the 

 Jlimberley diamonds than to those which originated the plumbago 

 deposits in North America, though there is great dissimilarity 

 in the chemical composition of the intrusive rocks in the two cases, 

 especially with regard to the quantity of magnesia present. He 

 suggests that the molten magma in its upward course passed through 

 a deep-seated stratum of highly carbonaceous material, and tore off 

 numerous fragments, the bituminous matter in which became acted 

 upon by heat, a farther alteration being subsequently caused by the 

 intrusion of the diorite. 



2. " Notes on the Valley -Gravels about Reading, with especial 

 reference to the Palaeolithic Implements found therein." By 0. A. 

 Shrubsole, Esq., E.G.S. 



The following deposits containing implements are described : — 



A. North of the Thames. 



(i) Gravel at Toot's Farm, Caversham ; 235 feet above sea- 

 level, 

 (ii) Clayey gravel by side of Henley Road, Caversham ; 168 feet 



above sea-level, 

 (iii) Subangular gravel at Shiplake ; 200 feet above sea-level. 



B. South of the Thames. 



(i) Gravel at Elm Lodge Estate, Reading; 197 feet above 



sea-level, 

 (ii) Gravel on disturbed beds at Redlands ; 157 feet above 



sea-level, 

 (iii) Comminuted flinty gravel at Southern Hill; 223 feet 



above sea-level. 

 (iv) Gravel at Sonning Hill ; 185 feet above sea-level, 

 (v) Gravel at Ruscombe, Twyford ; 165-170 feet above sea- 

 level. 



The author concludes that the highest gravels (235-280 feet 

 above sea-level) do not, so far as is known, contain any traces 

 of man, and that a considerable amount of vailej T -erosion occurred 

 before the deposition of the earliest gravels which have furnished 

 human relics. Further, he considers that the deposits indicate the 

 occurrence of a severe climate at an early stage, and its recurrence 

 at a later one, viz. during the deposition of the gravels found at a 

 height of 197 feet and 144 feet respectively above the sea-level. He 

 believes that many of the implements found in the lower levels 

 at Reading have been derived from gravels of various dates and 

 different levels, which have been swept away by denudation, and 

 that this will account for the mixed character of the types of 

 implements. 



