£. Neaverson—Foraminifera of the Hartwell Clay. 455 
exposures of Hartwell Clay, and the results are given below. 
A series of the Foraminifera has been deposited in the Aylesbury 
Museum. 
_ Previously the Foraminifera of this interesting deposit had received 
scant attention. A short list is given in the Geol. Surv. Memoir by 
H. B. Woodward (Middle and Upper Oolites, 1895, p. 227), but on 
account of the terminology employed, some revision appears 
necessary. In 1897 F. Chapman recorded fifteen species from 
Hartwell (Proc. Geol. Assoc., vol. xv, p. 97), remarking that they 
“present a facies comparable with that of the Neocomian (sic) 
and Gault”. No other lists appear to have been published, and the 
forms have not yet been described. 
Foraminifera from beds of approximately the same age have been 
described by :— 
Chapman (Tithonian Foram. Stramberg; Linn. Soc. Journ. Zool., 
vol. xxviii, 1900, p. 28) ; 
Perner (Ueber Foram. Tithon, Stramberg: Bull. Acad. Bohéme, 
ISOS Sip ew) imand 
Haeusler (Die Astrorhiziden und Lituoliden des Bimammatus 
Zone; N. Jahrb., 1883, vol. i, p. 55). 
Other works consulted are indicated in the text, but the synonymy 
is reduced to a minimum, only a few of the more important references 
being given. 
The writer is indebted to Mr. E. Hollis for help in the collection 
and preparation of material, to Mr. 8.8. Buckman, Mr. C. P. Chatwin, 
and Dr. A. Morley Davies for kindly criticism and suggestions, to 
Professor P. G. H. Boswell for reading the manuscript; also to 
Dr. F. L. Kitchin for an opportunity recently of examining 
Chapman’s specimens of Gault Foraminifera, now in the Museum 
of Practical Geology. For this assistance the writer wishes to express 
his gratitude. 
NotTES ON STRATIGRAPHY OF THE BeEps. 
A combination of circumstances renders the determination of the 
zonal sequence in the Hartwell Clay and underlying beds a matter of 
some difficulty. The number of exposures is limited, some of the 
brickfields have not been worked for a considerable time, the 
workings are shallow, and the ammonites usually in a fragmentary 
condition. The identification of the ammonites also is not yet 
complete ; only a provisional indication of the horizons is therefore 
given. 
The typical Hartwell Clay is exposed at Hartwell, Aylesbury, and 
Bierton, and contains ammonites usually identified as Perisphinctes 
pallasianus (d’Orb.). This clay is overlain by the Portland Pebble- 
bed, which has weathered down to a sandy consistency. The clay 
at Whitchurch (5 miles north of Aylesbury) is probably on the 
same horizon as that at Hartwell, because, though it differs from 
the latter in the presence of selenite, fragments of ammonites occur 
