Vol. 65.] GEOLOGY OP THE NEIGHBOURHOOD OF SEAFOEB. 449 



kind, except near the base, where the zone of Micraster cor-anguinum 

 is indicated. Near Exceat Bridge there is a small disused quarry, 

 much obscured by talus, and very barren in fossils. Those found 

 here prove, however, that this quarry is below the level of the 

 Marsupites-Zone, as indeed would be expected by its position, less 

 than 50 feet above the level of the river. Proceeding next to the 

 known outcrop of the Marsupites-Zcme on Seaford Head, the junction 

 with the zone of Actlnocamax quadratus can be traced eastwards 

 from the Roman Camp to the south of Chyngton Barn, where a 

 small pit yields Cardiaster pillula in abundance and other fossils 

 characteristic of the Actinocamax-quadratus Zone,. The strike of the 

 beds here, therefore, is nearly east and west. At Chyngton Farm, 

 a low hill about 150 feet above the river is capped by an Eocene 

 outlier, which is well exposed in a small opening. It may 

 consequently be inferred that we have here the full thickness of 

 the zone of Actlnocamax quadratus, which is found to be 150 feet 

 on the east of Seaford Head. 1 The level of the Marsu/>ites-Zoue 

 here, therefore, must sink below the alluvium of the Cuckmere ; 

 and there is consequently a steep dip from the top of Seaford 

 Head, northwards, at an angle of 15° or 20°. There is, in fact, 

 between Seaford Head and Hindover a sharp bend, and a true 

 synclinal valley with dip-slopes in opposite directions, as shown 

 in the diagram (fig. 4, p. 450), the full significance of which will 

 be explained below. 



In tracing these outcrops I have tried to avoid loading the 

 description with detailed lists of fossils. It will, however, be use- 

 ful, before concluding this portion of the subject, to call attention 

 to a few points regarding the fossils collected from this area. 

 In the first place, I must again acknowledge the great value of 

 Dr. Howe's pioneer work, which I found to be not only a perfectly 

 trustworthy guide in the field, but also remarkably easy for even a 

 novice to assimilate and apply. In one point alone, as previously 

 stated, do the inland exposures appear to me to be in some dis- 

 agreement with the evidence in the cliff-section. I refer to the 

 band of Conidus albogalerus, found near the junction of the zones 

 of Marsup>ites testudinarius and Micraster cor-anguinum. Dr. Rowe 

 states that the large pyramidate form of Conulus is rare in the 

 cliff-section, and that no band of this fossil exists at this horizon 

 in the Sussex cliffs, although this band is usually found in Thanet 

 and elsewhere. I found, on the contrary, fairly numerous examples 

 of this species wherever there are good inland exposures of the 

 top of the zone of Micraster cor-anguinum. This is the case at 

 Friston, at Hindover (in two localities), and at Denton, in each 

 of which localities the presence of this fossil is very marked. I 



1 The possibility of some pre-Tertiary erosion must of course be admitted, 

 but of this there is no evidence, and it seems to be not unreasonable to conclude 

 that the thickness of the Actinocamax-quadratus Zone at Chyngton is as great 

 as it is at Seaford, which is only a mile away to the west. 



