DEPOSITS OF THE SUSSEX COAST. 355 



Turning now to the strata yielding evidence of a mild period, we find 

 characteristic fossils at two localities and in deposits of two distinct 

 types. The first is the well-known marine mud-deposit of Selsey ; 

 the other is the little-known freshwater and estuarine gravelly 

 loam of West Wittering. The Selsey mud-deposit has so often been 

 described that it is curious to find that two strata seem to be 

 included under the term. One of them probably gives the name, 

 the other yields the characteristic southern fossils. A section, seen 

 nearly a quarter of a mile south-east of Thorney Gap during the 

 recent gales, is shown in fig. 2, but under ordinary circumstances 

 little or nothing is visible between tide-marks, except beach-sand 

 and the Bracklesham Clays. 



Fig. 2. — Section of tlie cliff and foreshore at Selsey Bill. 





(Scale, vertical, 20 feet = l inch ; horizontal, 100 feet= I inch.) 



feet 

 6. Stonv loam, gravelly at base, chalky where nnweathered (= Coombe 

 Eock) 6 



{' Shingle, with occasional fragments of Greensand chert and other 

 erratics ('= Raised Beach of Brighton ?) 4 

 Sand and shingle 3 



Hidden under recent beach fprobably all sand and shingle, as above)... 6 

 4. Black, stony, estuarine mud, with driftwood, acorns, Scrobicularia in 

 the position of life, Hydrohia ulvcB, Littorma obtusata, Rissoa xjarva, 



Utriculiis, Tellina balthica, Cardium edide 2 



3. Stonj- clay with numerous re-deposited erratics (base of TsTo. 4) O.^- 



2. JBard greenish clay, full of derivative Bracklesham fossils, and with 

 Pleistocene marine mollusca. Chiton siculu.% Bissoa cimex, &c. 

 Occasional large Chalk flints and erratic blocks. (Thi< deposit is 

 likely to be confounded with the underlying Eocene strata, for it is 

 mainly foi'med of re-deposited Bracklesham material, and contains 



more Eocene than Pleistocene fossils) 2 



1. Bracklesham Beds. 



The first thing to strike one in this section is that three diff'erent 

 types of sediment are represented among the brackish-water and 

 marine strata. The lowest bed is a purely marine deposit, with a 

 molluscan fauna of southern type, showing a depth probably of 10 

 or 25 fathoms. The next is a Scrobicularia-m.\id, with estuarine 

 shells and land-plants, and was clearly formed between tide-marks. 



