196 GEOLOGY OF THE ISLE OF WIGHT. 



like those immediately below tlie marine beds — a comparison of 

 the measurements shows that they ought to be within 4 feet of 

 the Gerithium jjlicatum bed. 



We will take next the rest of the sections in the West Medina, 

 none of which show continuous exposures of any o-reat thickness 

 of beds. Commencing with the cliffs, we encounter Hamstead 

 Beds for more than two miles, from near Yarmouth Toll Gate to 

 above Hamstead Ledge. Then travelling eastward we pass over 

 a gap of two and a half miles, to Thorness Cliffs, where the ]31ack 

 Band again strikes the coast, much overgrown and hidden by 

 landslips. From Thorness to Sticelett the cliff sinks, but in the 

 higher cliff near the latter place the Black Band is well seen, 

 overlying Bembridge Marls with the usual seam of Melania 

 muricata and Hydrohia Chosteli. Still further to the north it may 

 again be examined in a small outlier cut through by the cliff. In 

 both sections the Hamstead Beds are much weathered, only the 

 lower part being exposed. 



Taking next the inland sections of the Black Band, we 

 will give the evidence on which the division has been made 

 on the map between the Hamstead and the Bembridge Series, 

 commencing with the north side of the syncline. 



Above Hamstead ledge the Black Band strikes inland in a 

 iouth-south-easterly direction. There was formerly a large brick- 

 yard at Lower Hamstead, but this is now overgrown. However, 

 a boring (B.H. 276) was made in the pit near the cottage. This 

 proved hard brown and bluish-green clays, like those 50 or 60 

 feet up in the Hamstead Beds. So another boring (B.H. 277) was 

 put down on the northern shore of the creek immediately north 

 of the brickyard. This proved beds crowded with Gyrena 

 semistriata and Entomostraca. Another boring (B.H. 278) close 

 to the shed at the Saltworks was in tough blue clay, in the upper 

 part full of Paludina and Nematura. Unfortunately the speci- 

 mens were destroyed, and it is uncertain whether the Nematura is 

 the typical N. pupa or the other form which occurs lower down 

 and near the Black Band. At any rate the outcrop o£ the Black 

 Band lies only a few yards further north. 



Eastward the base of the Hamstead Beds disappears under the 

 wide alluvial flat north of Newtown. A boring (B.H. 275) north of 

 Newtown Coastguard Station proved hard clays like those found 

 at Lower Hamstead. Another boring (B.H. 274) on the southern 

 margin of Clamerkin Lake showed the bed with Gyrcna and 

 Entomostraca, as in B.H. 277. A third boring (B.H. 27l), further 

 east and near Clamerkin, proved the Bl?,ck Band. Beyond this 

 point the strike changes and gradually curves to the north round 

 Porchfield. 



At Locksgreen, close to the Smithy, the Gyrena bed was met 

 with (B.H. 270). A quarter of a mile south of Porchfield the 

 Black Band was reached (B.H. 268), and two other borings 

 (B.H. 269 and 267) also pierced the lower part of the Hamstead 

 Series. Haifa mile east of Porchfield two borings (B.H. 264 

 and 263) were perhaps sunk in the lower part of the same Series, 



