220 Revieius — Geology of Bournemouth. 



I. — The Geology of the Countei' akound Bournemouth. Explana- 

 tion- OF Sheet 329 (Netv Series). Memoirs Geological Survey 

 England and Wales. Second edition. Ey H. J. Osboene-Whij:e^ 

 F.G.S. pp. vi + 79. London, 1917. Price2s.net. 



TMHIS memoir, which is published as a second edition, is really 

 JL a new book. The first edition, written by Mr. Clement Eeid^ 

 was very brief, as it was intended at the time to publish a general 

 memoir on the Hampshire Basin. This not being possible, a second 

 edition of the sheet memoir has been issued in which the geology of 

 the district is fully described. The book is written in an interesting 

 manner ; a chapter is devoted to each series of rocks, and is made up 

 of a general section followed by more detailed description of the 

 particular exposures. In the general sections the geological history 

 of the district is clearly brought out. The oldest rock in the area 

 covered by the map is the Upper Chalk. At the close of Cretaceous 

 times the district was uplifted and denuded, and the Heading Beds 

 rest on a surface which shows well-marked evidence of erosion. 

 These beds are of freshwater origin. The London Clay, which 

 follows them, is of the sandy type showing shallow-water conditions, 

 and is becoming thinner to the west. The Bagshot and Bracklesham 

 Beds are classified according to the old plan and not accordingto that 

 proposed by Mr. Gardner, owing to the difficulty of separating the 

 pipeclays and sands of Corfe and Poole from the Bournemouth fresh- 

 water series in the inland exposures. These show a shoaling of the 

 water culminating in the Bournemouth freshwater series. 



Throughout Bracklesham time the water became gradually deeper, 

 and the Barton Clay shows true marine conditions. This was followed 

 by another shallowing of the water as shown by the Barton Sands, 

 and the highest Tertiary rocks in the area, the Lower Headon Beds, are 

 deltaic in character. From evidence obtained elsewhere the Oligocene 

 sea must have spread over this region, but the deposits have all been 

 removed. The only record of Miocene or Pliocene times in the 

 district is the slight flexuring of the strata, which must correspond to 

 the more violent movements observed in the Isle of Purbeck and the 

 Isle of Wight. 



The Pleistocene deposits are well represented. Gravels are found 

 at many different levels, and have been divided as follows : high 

 plateau, 300 ft. ; highest terrace, 200 ft. ; Eolithic terrace, 150 ft. ; 

 Palaeolithic terrace, 100 ft. ; Bransgrove terrace, 60-80 ft. ; Valley 

 gravels on the valley floors from 30 to 40 ft. above O.D. These all 

 consist of subangular flints and quartz sand, and have been laid 

 down in running water. No organic remains have been found, but 

 implements of Chellean and Acheulian types have been found in the 

 Palseolithic terrace. The rivers which deposited the older of these 

 gravels probably drained into the "Solent Biver", which was 

 a continuation of the Frome, and whose valley was not breached by 

 the sea till after the deposition of the Bournemouth plateau gravel. 

 The character of these plateau gravels, when compared with that of 

 the modern alluvium, shows that the volume of water in the ancient 



