1848.] PRESTWICH ON STRATA OF CHRISTCHURCH HARBOUR. 45 



Section of the Cliff at Hengistbury Head. 

 Fig. 2. 



Feet 



Ochreous flintgravel. 



Sandy clays. 



White clayey sands full 

 of vegeta )ie remains. 



Clay much mixed with 

 sands, white & green. 



Dark grey clay much 

 mixed with patches of 

 greensand. 



Rounded flint pebbles 

 in white sand. 



These beds form one se- 

 ries, and pass one into 

 the other. It contains 

 large, flat, very ferru- 

 ginous septaria full of 

 carbonized vegetable 

 fragments and with a 

 very few casts of shells. 

 In the lower bed of 

 clay casts of shells are 

 also very rarely found, 

 but in parts of the clays 

 above they are not un- 

 common; a few pebbles 

 occur throughout. 



Whitish sand full of small fragments of carbonized vegetable 

 remains. About ^ mile west of the headland the car- 

 bonaceous matter so greatly increases, that the upper part 

 of the sand for a thickness of 5 feet passes into a black 

 carbonaceous sand. The thickness of this stratum is 

 not seen in this part of the cliflFs. 



have the same well-marked bed of black flint pebbles, varying in size 

 from a marble to a swan's egg, and imbedded in white and yellow 

 sand and forming a perfect gravel-bed. Above these are the clays, 

 rather more sandy, it is true, at Hengistbury Head than in Barton 

 cliff and the septaria more ferruginous, but with no character of any 

 value as indicating difference of origin. In further corroboration we 

 have the evidence, scanty though it be, of organic remains. In the 

 lower part of the clay at Hengistbury Head they are extremely 

 scarce : I only found one cast of a small Modiola and some teeth of 

 the Lamna. Rather higher in the section, and at a short distance 

 west of the Head, I however found very friable, but abundant re- 

 mains of Barton clay species of Panopsea, Solen, Cytherea, Pectun- 

 culus and Venericardia. Of themselves these few fossils would be 

 insufficient to determine the age of these clays. Several of them 

 equally mark the Bracklesham beds, though on the whole they pro- 

 bably more resemble those of the Barton clays ; but this fact being 

 supported by a superposition and by lithological characters, agreeing 

 with the lower beds of the Barton clay at Barton, it follows that the 

 weight of evidence is in favour of their belonging to this series. I 

 had not time to work out more fully the organic remains of this bed, 

 but a further search would, I am convinced, bring many more to 

 light. There is a brick-pit recently opened immediately on the eastern 

 side of the headland, at which I requested the men to collect any 

 specimens they might meet with. 



The septaria, although containing almost exclusively carbonized 

 fragments of plants and imperfect vegetable impressions, also showed 

 traces here and there of shells. The *' Teredo antenauta " was far 

 from uncommon in some of the large fossil stems of trees which are 

 found both in the clays and in the septaria. I would also call atten- 

 tion to the occasional occurrence, in a tolerably perfect state, of the 



