HEADON HILL AND COLWELL BAT IN THE ISLE OP WIGHT. 125 



at first identified with Sowerby's species, but subseqnently altered 

 to M. hartonensis (Ed. MS.) ; we cannot, however, see any distinc- 

 tion between these and M. producta (Ed. MS.) from Colwell Bay ; 

 we consider them all one species. Mr. Searles Wood doubts the 

 Hamstead form M. minor, Eorbes, being a distinct species either. 



Corbida pisum (Sow.) is not in Edw. coll. from Headon Hill or 

 Hordwell ; and we doubt its occurrence there ; it is, however, fairly 

 abundant in the Brockenhurst zone of Whitecliff Bay. C. nitida 

 (Sow.) is in Edw. coll. from Roy don and Long Mead End ; it was 

 originally described from Prof. Sedgwick's specimens brought from 

 Middle Headon beds. 0. fortisulcata (Ed. MS.) we consider merely 

 a variety of C. pisum ; we omit it, since it comes from Long Mead 

 End, probably from Barton beds. C. jicus was found at Brocken- 

 hurst by one of the authors, and is now in the Woodwardian Mu- 

 seum. 



Panopcea corrugata (Sow.) is, according to the Edw. coll., only a 

 Barton and Bracklesham shell ; but quite possibly P. subeffusa (Ed. 

 MS.) is not really separable from this species ; in either case one of 

 the names must be omitted. 



Cyrena subregularis (Ed. MS.) seems to pass into C. obovata (Sow.). 

 0. deperdita (Lam.) is in Edw. coll. from Headon Hill and Barton ; 

 it is probably from the Lower Headon. O. arenaria (Eorbes) in 

 Edw. coll. is scarcely separable from the preceding; it is from 

 Headon Hill and Hordwell, but apparently from Lower Headon. 

 Mr. Searles Wood figures a different form as Eorbes's species. C. 

 gibbosula (Morr.) is scarcely a distinct form. C. cestiiarina, C. alti- 

 rujpestris, 0. obliquata, MS. names in Edw. coll., are not inserted ; 

 they may probably be Lower-Headon shells. 



Bdlanus unguiformis (Sow.) we found as frequent at Headon Hill 

 as at Colwell Bay. 



Pollicipes refleccus (Sow.) is cited by Eorbes from Colwell Bay. 



Callianassa Baylii (H. Woodw.) we have from all the zones of 

 the Middle Headon. 



EXPLANATION OF PLATE V. 



The figure represents the coast-section from Headon Hill east of Heather- 

 wood Point to Cliff End, Colwell Bay ; it passes inland at Warden Point 

 to avoid the projecting promontory. An attempt is made to represent 

 where beds may be seen in situ, and where they are concealed by fallen 

 material. Notwithstanding that the vertical scale is more than double 

 the horizontal, it is impossible to show much detail ; and for this refe- 

 rence is to be made to the accompanying vertical sections (pp. 91, 98, and 

 103). 



The bends of the coast-line are approximately indicated by the com- 

 pass-bearings given. 



Discussion. 



The Pkesident remarked that the paper was one of great impor- 

 tance. The question at issue was one sharply defined but difficult 

 to come to a conclusion upon without visiting the sections. 



