456 Morris — Ferruginous Sands of Buckinghamshire. 



This species occurs in the Upware deposit, and also in the con- 

 glomerate bed near Potton ; in the former the specimens are cal- 

 careous, in the latter ferruginous. Calcareous casts of the interior 

 also occur at Upware. 



By its remarkable form, this species is easily distinguished from 

 aU other Cretaceous TerebratulcB. 



I have great pleasure in naming this fossil after my friend W. S. 

 Dallas, Esq., F.L.S., etc, 



DESCRIPTION OF PLATE XIX. 



Fig. 1. Terebratula LaUasii from near Potton. 



2. Terebratula LaUasii, from near Upware. 

 la & 2a. Dorsal aspect of sheU, 



\b & 2b. Side view of same. 



Ic & 2c. View of anterior margin of valves. 



3. Waldheimia Woodwardii, from near Upware. 

 3a. Dorsal aspect of shell. 



36. Side-view of same. 



3c. View of anterior margin of valves. 



Zd. Ditto, cast of interior, from the same place. 



4. Waldheimia Duvidsonii, from near Upware. 

 4a & 4c. Dorsal aspect of shell. 



Ab. Side-view of same. 



Ad. View of anterior margin of valves. 



V. — On the Fekruginous Sands of BuoKiNaHAMSHiRE, with 

 Eemaeks on the Distkibution of the equivalent Stkata. 



By J. MoKRis, F.G.S. 



THE coarse ferruginous sands at the base of the Cretaceous 

 series, in the counties of Bedford and Cambridge, have of late 

 years attracted considerable notice, not only as sources of iron ore, 

 but also of phosphatic matter. To these deposits the attention of 

 geologists has been directed, and among other valuable papers, 

 may be mentioned some by Messrs. Seeley and Walker,' who have 

 •treated of their general physical characters, and also of their in- 

 teresting fossil contents. It may be useful to some of the readers 

 of the Geological Magazine, who are interested in tracing out the 

 range of this deposit, and the peculiar conditions under which it 

 was accumulated in some parts of the area, to point out briefly its 

 characters and contents in the adjoining county of Buckingham ; 

 ■i.e., around Aylesbury^: more especially so, as these sands have been 

 considered to be partly equivalent in time, or the marine conditions 

 of the Wealden and Purbeck strata. 



These beds vary slightly in mineral character in the district to be 

 noticed ; the most marked or predominant feature being, however, 



1 Ann. and Mag. Nat. Hist., Aug., 1866 ; July, 1867. Geol. Mag., Vol. IV. 

 p. 199, Ann. and Mag. Nat. Hist., July, Nov., 1866 ; Aug., 1867. Brodie, Geoi. 

 Mag., Vol. III. p. 153. Walker, Brit. Assoc. Dundee, Sept., 1867. See also 

 Original Article IV. in this number of the Geol. Mag. 



* A part of this district being uncovered by Drift or Boulder-clay, good sections of 

 the Lower Greensand, Purbeck, Portland, and Kimmeridge clay may be seen, and a 

 little to the north, in the railway cutting, the Oxford clay. See " General Sketch of 

 the Geology of Hartwell," London University Magazine, June, 1856, p. .102. 



