HEAD ON HILL AND C0LWELL BAT IN THE ISLE OF WIGHT. 



113 



would entail the abandonment of the names Upper and Lower also. 

 There is therefore no room for the term " Brockenhurst Series " in 

 the sense proposed in the paper referred to {op. cit. p. 16S) — a 

 classification which would be in conflict with the best authorities, 

 and founded, as we have endeavoured to show, on a defective appre- 

 ciation of the beds. We may urge that no new facts have been 

 discovered concerning the succession of the strata to make any 

 correctionary classification or nomenclature in the main groups of 

 the Upper Eocene at all necessary or desirable, and we should prefer 

 to retain the local groupings which have been so long familiar to 

 geologists. "We may denote as the " Brockenhurst Beds " the lower 

 part of the Middle Headon with the rich Brockenhurst fauna. It 

 is not always developed ; the absence of admixture of fresh water 

 was evidently the necessary condition of its abundance of marine 

 mollusca and of the existence of its corals. 



It may perhaps be subdivided into the " Brockenhurst zone " and 

 the "Eoydon zone"*. The correlation of this fauna was justly made 



* We found the Eoydon brick-yard pit in a good state for examination this 

 summer, and obtained from it twenty-eight species. They all came from the 

 sandy clays with bands of iron-ore septaria ; the lowest beds were below the 

 level of the standing water. The section is as follows : — 



Gravel. Post-Tertiary. 



2-3 feet. Bluish to yellow-grey clay. 



9 inches 



{" 



Shell-bed ; " clay very full of 

 shells. 



Nurcx sexdentatus, Cardita ob- 

 longa var. transversa, Pisania 

 labiata, Trigonoccelia deltoidea, 

 Ostrca velata, Cytherea incras- 

 sata, Cyrena obovata var. sub- 

 regularis (Ed. MS.). 



f Grey clay. 

 Two nodule-bands of iron-ore 

 7^ feet, j septaria separated, by grey 

 sandy clay. 

 Stiff bluish clay for the lower 2 

 ( feet. 



feet. Greenish-grey clavev sands. 



f Voluta gcminata, Voluta spinosq, 

 Strepsidura armata, Pleuro- 

 toma transversaria, Pleu.ro- 

 toma hantonicnsis, Natica 

 epiglottina, Bulla LamarcJcii, 

 Protocardium han toniense, 

 Cytherea suborbicularis, Psam- 

 mobia cestuarina, Corbula 

 \ piswn, &c. 



Eeposing on Lower Headon fresh- 

 water clays. 



The shelly bed, we consider, represents part of the Venus-bed or Headon- 

 Hill marine zone, since it contains the characteristic oyster and Murex sexden- 

 tatus, &c. 



The clays and clayey sands below, of which we examined 7 J feet, while, 

 according to the statement of the men employed, the remaining sandy beds 

 below are another 7 feet, we propose provisionally to term the i: Eoydon zone." 

 It is characterized palreontologically by the abundance of Voluta geminate, 

 differing from the "Brockenhurst zone" by the absence or great rarity of Valuta 

 snturcdis, Pleurotoma cymcea, and Cytherea Solandri, for the latter shells are 



