HAMSTEAD BEDS. 199 



At the Reservoir about 50 feet above this level there seems to 

 be some representative of the White Band, for J. Rhodes 

 obtained from the spoil-heap Mya minoi-, Cerithium, Cyrena 

 semistriata, Cytheridea Mlllleri and a new species of Cytheridea 

 (Fig. 78.) However, no white marl like that of Hamstead Cliff 

 is visible at this spot. 



Fig. 78. Havincr traced the base of the Hamstead 



Cytheridea montosa, Series till it has now passed out of reach 

 Jones and beneath the sea-level, we will follow the south- 

 Sherborn.* ern margin of the syncline from Yarmouth 

 to Newport, taking afterwards the higher beds 

 met with here and there in the West Medina. 

 It will be remembered that the Black Band was 

 traced on the foreshore to within a quarter of 

 a mile of Yarmouth Turnpike (see p. 1 96). In 

 the overgrown cliff it was again found 200 

 yards further west, and a boring by the side 

 «• ^- of the high road (B. H. 355) reached it at 



&: Ed1l*view;een ^ ^^^P^^^ ^f 13 feet, showing that the Ham- 

 from the ventral stead Beds must extend westward along this 

 margin. ridge to within 130 yards ol Yarmouth Turn- 



Magnified 20 diam. pil<e. 



Half-way between Bouldnor and West Bouldnor, and also a 

 quarter of a mile south-east of Bouldnor, the Black Band is 

 again met with (B.H. 352, 348). Then the strike suddenly curves, 

 and the Hamstead Beds extend southward in a tongue corre- 

 sponding with the similar feature in the Bembridge Limestone. 

 This curve is proved by a boring (B.H. 334) in the lane north of 

 Lee Farm, and by another (B.H. 332) a quarter of a mile north of 

 Freeplace, but as these only show the usual character of the 

 Black Band there is no need to give the details. 



Near Ningwood the position of the base of the Hamstead Series 

 is exactly fixed by a series of borings, all reaching the Black 

 Band (I3.H. 325, 321, 319, 317, 314, 313). South-east of 

 Shalfleet the boundary makes another sudden bend to the 

 south, this time approaching the Chalk so closely that the 

 beds come within the influence of the more violent flexure and 

 have a high northerly dip. It is therefore often difficult to strike 

 the exact base in a boring, though its place can be fixed within 

 a chain of its true position. 



Two borings at Stonesteps (B.H. 296 and 297), within a chain 

 of each other, show, the one Bembridge Marls, the other free- 

 cutting loams some distance up in the Hamstead Sei"ies. A 

 boring (B.H. 295) on the road to Fullholding happened to 

 strike the Black Band at 4 feet below the surface, while another 

 (B.H. 292) close to Fullholding reached it at 16 feet, though this 

 latter commenced at a level 30 feet lower. There must be an 

 average northerly dip of about 3° between these points, probably 

 the dip is much higher at the first boring and rapidly decreases 



* Siippl. Monogr., Tert. Entom. Pal. Soc, 1889. 



