and on the Drift uf the Eastern Counties. 189 



with both valves united, and univalves with the puUus unim- 

 paired. This bed, lying at the southernmost extremity of the 

 deposit, presents the only instance of Red Crag, other than that 

 of the fifth stage, which has been deposited under water ; and 

 it is destitute of those derivative Coralline-Crag shells that so 

 largely contribute to make up the mass of the rest of the Red 

 Crag. The rest of the Red Crag, occupying as it does a hollow 

 between the Coralline Crag on the one side and the London- 

 Clay shore on the other, is largely composed of the degraded 

 material of the Coralline Crag, as well as having been in each 

 successive stage largely made up of the degraded material from 

 the preceding stages. 



The fifth stage, or horizontal and water-deposited Crag, does 

 not uniformly cover the underlying beach stages ; these, deeply 

 furrowed on their surface, are very frequently covered only by 

 the red sands of the lower Drift ; while the manner in which 

 the fifth stage spreads up to and over the beach stages (almost 

 always the fourth) shows that it has been formed in channels 

 cut through the pre-existing beach, and afterwards silted up. 

 It is under this fifth-stage Crag alone that the workings of 

 phosphatic nodules, so far as I have seen them, occur*. I learn 

 from Mr. Colchester that this material has been obtained from 

 beneath the Coralline Crag ; but not only have all the nodule- 

 workings in the Red Crag that I have visited been under this 

 stage, but wherever the beach stages are to be found resting 

 on the Clay, as at Bawdsey and Walton, the nodule- band does 

 not occur. This band, often of nearly a foot in thickness where 

 worked, and largely intermingled with rolled PectuncuU, thins 

 off gradually as the fifth-stage Crag leaves the Clay and rises 

 over the beach stages. I have traced it so rising in numerous 

 instances. At the watercourse near Methersgate Dock, Sutton, 

 it appears overlying beach stages, whence, going eastwards, 

 the extensive (but now discontinued) nodule-workings imme- 

 diately over the London Clay occur ; and on quitting them, the 

 band rises again, on the eastern side, over beach stages. At 

 Bawdsey the band first occurs high up in the cliff, covering 

 beach stages, and descends to the southwards towards the river, 

 nearer to which, and inland, extensive workings have taken 

 place. At Tattingstone it occurs at the top of the section, 

 underlying fifth-stage and covering beach Crags, while at the 

 junction there of the beach Crag with the Coralline Crag it is 



* At the base of the beach Crags small nodules may be found, forming 

 a thin band interspersed with Crag ; but they are intermixed with pebbles 

 in such proportion that the pebbles are to the nodules as nearly 10 to 1. 

 There is no similarity whatever between these minute bands and the true 

 Pectuncultts-\e\n of nodules. 



