PRESTWICH WOOLWICH AND READING SERIES. 85 



Clarendon Hill, Hampshire'^ {several small pits in a brick-field). 



London Clay. Feet. 



I. Basement-bed of the London clay (flint-pebbles in clay and sand) ... 1 



. / Mottled clays with a few subordinate beds of sand, about 45 



'^\ a. Flints and pebbles in green sand and clay 1 



Chalk. — 



47 



Pebble Hill, Berkshire {section from two 'pits in nearly adjoining 

 brick-fields). PL I. Diag. A, Loc. sect. 2. 



London Clay. ft. in. 



I. Basement-bed of the London clay (flint-pebbles in clay and sand) 9 



"Light mottled greenish clay 10 



Irregular bed of sand 5 



Sandy grey and brown clay passing into slightly mottled clay ... 25 



II. •( Red tile clay 5 



Fine sand 3 



Band oi Ostrea Bellovacina 3 



La. Flints and pebbles in green sand and clay 1 



Chalk. 



49 

 In Marlborough Forest the tertiary beds are so thin and so dis- 

 turbed by, or mixed with, drift, that no good sections can be obtained ; 

 enough, however, is exposed to see that they consist of mottled clays 

 with sands and pebble beds reposing upon chalk. At Bagshot Hill, 

 two miles west of Hungerford, the series is more complete, but is 

 badly shown, and consists of the following beds : — 



Bagshot Hill {section from a few small pits and road-side cuttings). 

 PI. I. Diag. A, Loc. sect. 1 . 



Feet. 

 I, Flint-pebbles in clay and sand, some blocks of puddingstone on surface... 3 



e. Laminated yellow clays and sands about 12 



d. Dark mottled clays, light green with bright red about 35 



c. Imperfect iron-sandstone and sand 2 



b. Yellow sand and green clayey sand, with a thin seam of i ysters at base... 8 ? 

 a. Ferruginous clay with small flint-pebbles OJ 



Chalk, with a very uneven surface. 



The Ostrea Bellovacina is the only fossil found in this section, 

 which is merely exposed in part and is given approximately. At 

 Prosperous Wood these beds are more sandy, and contain subordinate 

 layers of iron-sandstone 2 to 3 feet thick. At Inkpen mottled clays 

 again preponderate and are worked to some extent : they are not 

 fossiliferous. At Pebble Hill the irregular and undulating bedding 

 of the Reading series is apparent, both in the section taken by itself 

 or viewed in relation to the Wickham and Newbury pits. 



* See Quart. Journ. Geol. See. vol. vi. pp. 257 & 258 for fig. of this and the 

 following Section. 



t Group II. proI)ably would admit of as many divisions as the mottled clays at 

 Pebble Hill, but the section is too imperfect (the lower beds not being exposed 

 when I was there) to give the exact sequence and thickness of each bed : on the 

 whole also it is more argillaceous. 



