vil CRETACEOUS LAMELLIBRANCHIA. 
F. Dixon on ‘The Geology and Fossils of the Tertiary and Cretaceous Forma- 
tions of Sussex’ (1850 or 1852). This contains excellent figures of some Chalk 
Lamellibranchs by J. de C. Sowerby, but the descriptions of the species are very 
brief, or in some cases even omitted; moreover, the type-specimens appear to have 
been lost, and in many instances their original locality is not stated. 
The latest work on the Lower Cretaceous Lamellibranchs of England is that by 
W. Keeping on ‘The Fossils and Paleontological Affinities of the Neocomian Deposits 
of Upware and Brickhill’ (1883). Most of the original specimens described in 
that memoir are preserved in the Cambridge Museum. 
A few papers have been published from time to time on the Lamellibranchs of 
special horizons, such as those of the Cambridge Greensand by Seeley (1861) and 
by Jukes-Browne (1875, 1877); those of the Farmgdon Greensand by Sharpe 
(1853); those of the Chalk of Cambridge by Etheridge (1881); and those of the 
Chalk Rock by myself (1897). Various papers dealing with Cretaceous strati- 
eraphy give brief notes on some of the species of Lamellibranchs. 
The distribution of the Cretaceous Lamellibranchs of England is indicated in 
many books and papers on stratigraphical and local geology. The more important 
of those dealing with the Lower Cretaceous deposits are :—(1i) on the Isle of Wight 
by Fitton (1847), and by Bristow, Reid, and Strahan (1889); (11) on the Weald by 
Topley (1875); (i) on Farmgdon by Phillips (1871) ; 
Keepimg (1882) and others; (v) on Speeton by Lamplugh 
The distribution of Lamellibranchs in the Gault is given in great detail by 
Price (1879); in the Upper Greensand of Blackdown and Haldon by Downes 
(1882), in that of Warminster by Jukes-Browne (1896), and in the Upper Green- 
sand and Chloritic Marl of Maiden Bradley by Jukes-Browne and Scanes (1901). 
Amongst the more important works dealing with the zonal distribution in the Chalk 
are those by Barrois (1876), Meyer (1874), Jukes-Browne and Hill (1886-96), 
Griffith (1891), and Rowe (1900, 1901, 1903). 
The distribution of Cretaceous Lamellibranchs in different districts is also 
iv) on Lincolnshire by 
1889, 1896). 
— 
indicated in numerous memoirs issued by the Geological Survey other than those 
above referred to; and revised lists showing the general distribution of the species 
in the Upper Cretaceous rocks are given in the memoir on ‘ The Cretaceous Rocks 
of Britain,’ by Jukes-Browne, vol. 1, 1900, pp. 453—487, and vol. i (in the press). 
The following monograph deals with the Lamellibranchs of all the Cretaceous 
deposits of England, with the exception of the Wealden formation, which, it is 
thought, will be more satisfactorily studied in connection with Mollusca of the 
Purbeck Beds. The species found in the lowest part of the Speeton Series in 
Lincolnshire and Yorkshire are, as a matter of convenience, included in this work, 
although they may possibly prove to be of Upper Jurassic age. The families are 
here considered generally in the order given in Pelseneer’s classification. 
