108 



H. KEEPING AND E. B. TAWNEY ON THE BEDS AT 



Summary. — There is but one marine bed here, namely that in 

 the Middle Headon ; for the Colwell-Bay bed can be traced strati- 

 graphically into the Headon-Hill Venus-bed, and the palaeontological 

 evidence is in harmony with the stratigraphical. The place of the 

 Brockenhnrst bed is at a lower horizon in the Middle Headon ; but 

 it does not appear anywhere in the west end of the island. 



IV. Whiteclife Bat and New Foeest. 



Middle Headon of Whitecliff Bay. — We next have to raise a 

 more serious objection to the way in which the Whitecliff Bay 

 section has been interpreted. In mixing up all the beds in the 

 marine series there together and calling them Brockenhnrst series, 

 it seems to us that the question has been obscured, if not begged. 

 The statement is that the 100 feet of marine beds at Whitecliff Bay 

 are the equivalents of the 25 -feet of marine beds at Colwell Bay and 

 of the beds in the New Forest with the Brockenhurst fauna (op. cit. 

 p. 148). Hence the Colwell-Bay bed is placed in the Brockenhurst 

 series, which is said to occupy a higher horizon than the Headon- 

 Hill and Hordwell marine bed ; and this view is indicated by dotted 

 lines in the vertical sections on p. 170. Since the 100 feet of 

 marine beds are classed together and called " Brockenhurst Series," 

 we suppose that the Brockenhurst fauna is imagined to occur 

 throughout them. As a matter of fact, that fauna is confined to 

 one zone, and that the very base of the series. 



Though we have worked over this part of the section bed by bed, 

 we need not here give all the details, but will refer to the description 

 of it on the Survey Vertical Section on Sheet 25. This series is 

 there justly referred to the Middle Headon, since it lies between the 

 freshwater Lower and Upper Headon, its total thickness read off 

 by scale being 90 feet. At the top are clayey sands and yellow 

 sands about 19 feet ; then the " Venus-bed " clays &c, 15 feet ; 

 next, below, are compact sands with nodules about 42 feet, said to 

 contain Sanguinolaria Hollowaysii * ; then come 14 feet of brown 

 clays, the base "greenish and brownish clay, very fossiliferous." 

 Now there is no doubt at all about the bed above and the Venus- 

 bed here being any thing but the Colwell-Bay and Headon-Hill 

 marine bed — its position and its fossils prove that ; the characteristic 

 Brockenhurst fossils are absent from it, and it is therefore certain 

 that it differs entirely from the Brockenhurst beds. 



The Sanguinolaria-sand differs lithogically from the lower part 

 of the marine series, both at Colwell Bay and at Headon Hill. Such 

 few fossils as we observed in it are distinctive, not of the Venus- 



tion. Moreover these collectors sought to obtain as many forms as possible, 

 but were not concerned in finding the same species in both localities ; and if 

 they found only a few stray examples at one locality of a species of which they 

 had a great number from the other, they were liable not to put a separate label 

 for the odd few, but to mix them up with the larger parcel. 



* A wrong determination ; the shell is Psammobia compressa, var. cestuarina, 

 Ed. MS. It occurs in the natural position of life, i. e. across the bedding. 



