2l8 EXCURSION TO WALTON AND FRINTON. 



and is at some points a fairly steep slope. It is often masked by 

 a mass of Crag sand, forming a talus of gentle gradient, on which 

 the collector can lie prone, and fill his boxes at leisure, regard- 

 less of comment from Philistines occupying the cliff-top or the 

 beach. The several beds extend inland, and outcrop succes- 

 sively on the western slope of the Naze peninsula, as shown on 

 the Geological Surve}' map. 



The effect of denudation on the various beds are characteris- 

 tic for each. The porous and fairly coherent gravel on the top 

 offers a vertical face. Never being saturated by the most pro- 

 longed rainfall, it remains in place till dislodged pebble by 

 pebble, as the supporting grains of sand are removed by direct 

 lateral lashing of rain or spray. The water it receives on its 

 level surface sinks in, and escapes westward over the edge of the 

 underlying clay into the Crag below. This clay, originally 

 assigned to the Chillesford clay, which in Suffolk is interbedded 

 with the Crag, is probably representative of the Post-Glacial 

 freshwater bed of Clacton cliff, a correlation now published for 

 the first time, and based partly on its lithological character and 

 that of the superincumbent gravel, and partly on the presence, 

 about midway in its thickness, ot a seam of peaty matter and 

 fossil wood, as at Clacton. This seam was of limited extent, and 

 has now disappeared with the recession of the cliff, but fortu- 

 nately some of the wood is preserved in the Club's collection at 

 Stratford. This Post-Glacial clay or loam offers a nearly 

 vertical face, being sufficiently sandy to absorb and discharge 

 rainfall without becoming pasty or slipping. The Crag below it 

 has a steep face for a foot or two, merging into the talus. Its 

 basement bed of water-worn bones, teeth and pebbles, derived 

 from the denudation in the Crag period of the London clay and 

 of some deposits of intermediate age, is seldom visible, but a 

 shark's tooth badly damaged, and a large piece of bone, were 

 among the finds of the day. The London clay, rising to some 

 30 feet from the beach, has generally a steep face, but here and 

 there springs oozing from the Crag have caused heavy slips, 

 breaching the bank, and furnishing the waves with broken and 

 semifluid material, incapable of resisting their transporting 

 power. 



Notwithstanding the evident recession of the brow of the 

 upper cliff, there is no perceptible difference between the high- 

 water line of the old and the new Ordnance maps. This may 



