792 REPORT—1899, 
The classification now proposed, which is based on paleontological evidence, is 
as follows :— 
Older Pliocene. 
Lenhamian 5 5 4 Lenham beds : : Diestien sands, 
(Zone of Arca diluvii) Waenrode ? 
Nener Pliocene. 
Gedgravian . : : .  Coyralline Crag . ° Zone a Isycardia cor. 
Waltonian ; : ; 5 Essex Crag 
(Zone of Neptunea contraria) 
Walton horizon . : .  Scaldisien. 
Oakley af . 4 .  Poederlien. 
Newbournian . e Red Crag of Newbourn, Sutton, and 
Waldringfield ; ; ) ‘Ananiaen 
{ Red Crag of Butley and Bawdsey 
EERE | (one of Cardium groenlandicum) 
Icenian 
Lower horizon . . Norwich Crag, Southern district. 
Upper os ss » Northern district. ) 
(Zone of Astarte borealis). if 
Chillesfordian . : . (Estuarine) 1] 
Chillesford Clay and Sands. J 
Weybournian . : . Crag of Weybourne and Belaugh | 
(Zone of Tellina balthiea) J 
Forest bed (so-called) series. 
An analysis of the characteristic mollusca of the different divisions respectively 
of the Crag here suggested shows a gradual diminution of the percentages of 
extinct and southern forms, and a gradual increase in northern and recent species. 
The difference between the Gedgravian (Coralline Crag) and Waltonian is shown 
to be less than has been supposed, and the former is here grouped as Newer instead 
of as Older Pliocene, as hitherto. 
The Crag of Little Oakley, near Harwich, from which the author has recently 
obtained nearly 800 species of mollusca, belongs to an horizon different from any- 
thing previously described, and serves to bridge over the interval between the Crag 
of Walton-on-the-Naze and that of Suffolk. Its fauna closely resembles that of 
Walton, but contains some boreal and arctic species unknown from that place, 
including Neptunea antiqua (dextral), N. carinata, and N. despecta, and repre- 
sents the period when northern forms were first beginning to establish themselves 
in the Crag basin. It is approximately and partly equivalent to the Poederlien 
zone of Belgian geologists. 
The Red Crag beds, the fossils of which are, with few exceptions, the drifted 
and stratitied shells of dead mollusca, seem to have been deposited either against 
the shore, or in shallow water in proximity to it, in land-locked bays or inlets. 
The position which these inlets successively occupied was from time to time 
shifted towards the north, in consequence of the upheaval of the southern part of 
the Orag area, described by the author in a former paper.’ These inlets were silted 
up, one after another, by masses of shelly sand, but as far as the evidence goes the 
beds composing the different zones do not overlap. The Waltonian deposits 
are confined to the county of Essex, the Newbournian occupying the district to 
the north of the river Stour, and the Butleyan beds occurring along a narrow belt 
extending northwards from Bawdsey at the mouth of the river Deben. The 
Tcenian deposits, which are found only to the north of Aldeburgh, are shown by their 
molluscan fauna to belong to a period considerably more recent than any part of 
1 Quarterly Journal Geol. Soc., vol. lii. p. 773, 1896, 
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