Upper Greensand. 223 



easily recognisable, which, indeed, is also the case much 

 further south. 



In the south-eastern part of Dorsetshire, the Upper 

 Greensand crosses the Isle of Purbeck from west to 

 east in a narrow line, overlying the well-known Pun- 

 field beds, and overlaid bj the Chalk of the long and 

 imposing ridge of Purbeck Hill, Knowl Hill, Nine 

 Barrow Down, and Ballard Down. The Greensand itself 

 makes no feature in the landscape. Fig. 75, p. 347. 



Striking east under the sea, the Upper Grreensand 

 barely escapes forming part cf the great sea-cliff of 

 chalk, that runs from Sun Corner near the Needles, to 

 Compton Bay below Afton Down, from whence, over- 

 lying the Grault, it crosses the Island to the sea close 

 under Bembridge Down. In this course, wherever the 

 Chalk Downs are narrow, owing to the high angle of 

 northern dip, there the line of Upper Greensand is 

 also narrow, but where the angle of inclination is com- 

 paratively low, there both Chalk and Greensand spread 

 over a broad space, between Mollestone Down and 

 Carisbrook. A large outlier of Upper Greensand, 

 capped by two outliers of Chalk, overlooks the sea on 

 the south side of the Island between Chale Bay and 

 Chine Head, the strata being nearly flat. 



In the area of the Weald of Kent and Sussex (fig. 72), 

 the Upper Greensand at the base of the escarpment of 

 the Chalk, sweeps round the vast oval, from East Wear 

 Bay, near Folkestone, to East Meon, near Petersfield, 

 and from thence to the sea at Eastbourne, near Beechy 

 Head, but not with absolute certainty all the way, for 

 only here and there can the Greensand be faintly 

 discovered, between the sea and Chevening, along a line 

 of about fifty miles in length. Beyond this point it 

 begins to get more distinct, and the malm-rock, fire- 



