194 



GEOLOGY OF THE ISLE OP WIGHT. 



of Ostrca callifera (Fig. 77) Is founded on some mistake. There 

 seem to be no strata in tlie Forest so high as the base of the 

 Cerithium plicatum bed. 



Fig. 77. 

 Ostrea callifera, Lara. 



The highest strata in the Forest are found immediately west of 

 the Signal House. Here an old gr.-vel pit has been dug, only a 

 foot and a half below the top of the hill, and at the bottom of it a 

 boring was made to a depth of 24 feet (B. H. 11). The surface at 

 this point is 273 feet above the sea, and the base of the gravel lies 

 at '266 feet. The strata passed through are red and mottled clays^ 

 like those immediately beneath the marine beds at Hamstead and 

 Wootton. Palndina occurred at 15 feet from the surface, but no 

 other recognisable fossils were met with. 



About 8 chains soutn-west of the Signal House another old 

 gr.avel pit lies at a height of 254 feet. In this a boring (B. H. 10), 

 commencing 10 feet from the surface, was carried to a depth of 

 33 feet, in alternations of red and carbonaceous clays, with 

 Melania, Faludma, Unio, and Chara in the lower part. This 

 boring is important, as the upper part seems to show strata that are 

 too much obscured to be measured at Hamstead. In this upper 

 portion — probably corresponding with some of the beds marked 

 " obscure," about 25 feet below the marine beds*— a tooth of 

 Theridomys was found at 1 1 feet, and another small mammalian 

 bone at 15 feet. Mammalian bones are of rare occurrence in the 

 Hamstead Series, and the finding of two specimens in a small 

 boring makes it probable that this horizon might turn out to be 

 exceptionally fossiliferous, if it could be examined in Hamstead 

 Clifi: 



Other borings continue the section in a southerly direction 

 (B.H. 12, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43) into lower 

 beds, but nothing of interest is met with till we descend to 170 

 feet. Here shell marls commence (B. H. 35), but it is difficult to 



* See section, p. 186. 



