TRANSACTIONS OF SECTION C. 511 



the Upper Marine Series,^ treating of the coast section between Bournemouth and 

 Highcliff; and a second paper, Part II., on the lower or Freshwater series.- He 

 states his reason for differing from the previous writers upon the succession of the 

 heds and their correlation with other localities. Mr. Gardner's researches are in- 

 tended to show that the celebrated Bournemouth leaf-beds immediately underlie the 

 true Bracklesham series, and are, unlike those of Alum Bay, of Middle and not of 

 Loiver Bagshot period, hitherto the received \'iew as to their age. The author has 

 also ascertained that a great portion of the cliffs between Hengistbuiy Head and 

 Bournemouth are of marine origin, and liighly fossiliferous. These marine beds 

 comprise two distinct characters, which the author traces across to Alum Bay in 

 the Isle of Wight. Mr. Gardner also differs from the Geological Survey in" be- 

 lieving ' that the so-called Upper Bagshot beds of the London basin do not belong 

 to that_ series, but are the equivalents of his Boscombe sands ; these sands, and 

 the marine Bournemouth beds being, according to his researches, the western equiva- 

 lents, or extreme shore-condition of the Bracklesham sea.' 



At Highcliff, nearly under Rothsay Castle, both tlie Barton and the Brackles- 

 ham series are exposed, the Barton being not more than 10 feet in thickness, and 

 the subjacent Bracklesham 40 feet. The section is revealed to the sea-level, and there- 

 fore liighly instructive. The Highcliff sands conformably underlie the Barton and 

 Hordwell series at an angle of 2° to the E. The remarkable promontorv of 

 Hengistbiu-y Head is mainly composed of strata contemporaneous with the Brack- 

 lesham series ; these Mr. Gardner would for convenience call the1 Bournemouth 

 beds. Hengistbury promontory in shape resembles a parallelogram obliquely trun- 

 cated at its northern extremity. The cliffs facing the sea on the south are" about 

 50 feet high, increasing to 100 feet on the north, both presenting bold escarpments 

 to the sea. 'The succession of the strata at Hengistbury Head, reading upwards, 

 comprises, 1, the Boscombe sands ; 2, a lower series of sand with green grains, and 

 an upper bed with ironstone ; and 3, the white Highcliff sand. The white sands 

 at Highcliff are 30 feet thick, being 12 feet thinner than the equivalent beds 

 at Alum Bay, where they measure about 42 feet.' The lowest series in the cliffs 

 at the headland Mr. Gardner terms the 'Boscombe sands,' which without any 

 doubt represents the chief mass of brilliantly coloured sands, about 750 feet thick, 

 at Alum Bay, known to all explorers of the island. These coloured sands are 

 numbered 25 and 26 in Professor Prestwich's section of the vertical beds in Alum 

 Bay.3 Mr. Gardner also notices another hill similar in contour to that of Hengist- 

 bury, about three miles to the north of the Head. This, St. Catherine's Hill, 

 possesses, like the headland, similar physical features, being flat-topped and having 

 abrupt escarpments on all sides, and 160 feet high. Both the Highcliff sand and 

 the Hengistbury beds occur in this hill, showing their connection and continuity 

 inland with the coast section. ' The correlation of the Hengistburv Head series 

 on the mainland with those of Alum Bay across the Solent admits of little doubt, 

 and they would appear to be represented at Alum Bay by the HujhcUf sands, 25 

 feet in thichiess, and equivalent to bed No. 28 in Professor Prestwich's section. 

 The Hengistbury Head beds appear to be the equivalents of bed No. 27 in the 

 Alum Bay section. The Boscombe sands represent beds No. 26 and 25 of Prest- 

 wich in Alum Bay, where they are 150 feet thick. It can be conclusively seen, 

 from examination of the cliffs in the Bay from Hengistbury to Bournemouth, that 

 there is a general sequence, and that the 'strata have an amount of dip or inchna- 

 tion sufficient^ in so extended a distance, to expose two complete series of beds, 

 the upper series being the continuation of the Boscombe estuarine sands, 100 feet 

 thick, and the lower series of sands and clavs, of marine origin, which Mr. Gardner 

 has provisionally termed the Bournemouth marine beds.' With Mr. Gardner's 

 paper in hand the most minute details of the coast may be followed,' from the 

 Head towards Bournemouth. These, both for physical and palaeontological details, 



' Quarterly Journal of the Geological Society, vol. xxxv. pp. 202-228. 

 « Quarterly Journal of the Geological Society, vol. xxxviii. pp. 1-15. 

 ' Quarterly Journal of the Geological Society, vol. ii. pp. 223-259. 

 ■• Loc. cit. pp. 217-226. 



