HAMSTEAD BEDS.' 189 



Section measured further ivest, bi the broken ground a feiv feet 

 above the shore, about 29° E. of S.from the buoy on Hamsiead 

 Ledge. 



Traces of White Band on the top of broken ground 

 Ground not seen .---.. about 

 Clay, weathering brown, with traces of Gyrena bands on the 

 weathered surfaces ..... about 



Ferruginous band, with fragments of shells 



Laminated clays, unfossiliferous ? - - . - 



Clays, with laminae of Gyrena semistriata - - - _ 



Dark tenacious clay, with two bands of Gyrena, the upper con- 

 taining numerous Nematura pupa and valves of Cyrena, often 

 perfect and united at the hinge - - . . 



Green clay, with Gypridte -.-.-- 

 Dark fossil-band, Planorbis on top of bed, GypridcB throughout, 

 associated with Melania muricata, M. fasciata, a smooth 

 Melania, Melanopsis fusiformis, Limncea, and Gyrena or Gyclas 

 Clay, with band of Gypridce and occasional Melania at the base - 



Clay .. - 



Clay, with compressed Paludina and seed vessels 



Measured {by facing) along the shore at loio water, under Hamstead 



Hill 



Ft. In. 



Shelly band with Melania, Hydrobia, Limncea, and Planorbis on top 

 of bed .--...-- 



Green clays, with Paludina and seeds - - - - 



White marl, with Paludina lent a - - - - 



Green clays, with bands of Paludina lenta and Melanopsis carinata 

 Blade Band, with reed-like plants, and Unio and Paludina at base 



As the Hcamstead Series, though of considerable" thickness, 

 presents no breaks and no marked lithological changes, special 

 attention may with advantage be called to its different fossiliferous 

 horizons that can be identilied inland. These, with their approxi- 

 mate distances above the Black Band, are as follows : — 



Feet. 

 Gorbula and Gerithium plicatum beds - - 224 to 256 



Water-lily and leaf beds - - - 140 



White Band ----- 65 



Nematura beds - - - - 30 



Black Band - _ . - _ o 



The Black Band was taken by Forbes as the base of the 

 Hamstead Series " for several reasons, and foremost, because it 

 is apparently the first bed that succeeds to those Nvhich terminate 

 the Bembridge marl at Whitecliff and elsewhere In the Isle of 

 Wight. This circumstance, combined with those of the beginning 

 of a new series of fossils, of which the Rissoa Ghasteli (Fig. 61, 

 p. 175) is the first conspicuous representative, of the disappearance 

 of others, and the probable indications of a terrestrial surface 

 indicated in some of the features, both of this bed itself and the 

 bed below it, may fairly warrant the choice of so well marked an 

 horizon." 



