F. W. HARMER ON TILE KESS1NGLAND CLIFF-SECTION. L3o 



at Kessingland for a distance of 1200 paces towards Pakefield, ter- 

 minating abont 500 paces south of the Lighthouse gorge*. 



It is composed of an unstratificd tenacious clay of a slate-blue 

 » colour, occasionally mottled with brown, and sometimes containing 

 patches of brownish stratified sand. It is shown in places to be 

 underlain by sand and indurated gravel ; and its upper surface is 

 throughout penetrated perpendicularly by rootlets. It contains mi- 

 nute particles of chalk, specks of carbonaceous matter, and a few 

 small stones ; and from it, and from the underlying gravel, mamma- 

 lian remains are obtainedt. At its northern termination, where bed 

 No. 3 rests upon it, freshwater shells, chiefly Unio tumid us, occur 

 at its base, and in the gravel-bed below it. Its upper surface is re- 

 markably even ; and it is occasionally overlain by a few inches of sand 

 or indurated gravel. Its greatest thickness seems to be about 8 

 feet. 



No. 3, which is about 6 feet at its greatest thickness, fills a lenti- 

 cular hollow, cut out of beds Nos. 1 and 2, as shown in the accom- 

 panying sections. It is not penetrated by roots, as is No. 2, but 

 contains at its base an accumulation of wood debris. It is finely 

 laminated, and extends about 250 paces from end to end, being shown 

 in placesij: to be underlain by sand and gravel. It varies in colour and 

 composition, resembling at its southern end the black unstratified 

 clay on which it there rests, while northwards its colour changes to 

 a rusty brown. Unfortunately the section is now (March 1876) 

 much obscured by talus, especially at the point where in November 

 187-1 I saw the junction between beds Nos. 1 and 3 so clearly ex- 

 posed. The view has been consequently advanced that the lami- 

 nated clay, No. 3, is merely the continuation of the Chillesford Clay, 

 No. 1. To this I reply, that the two beds differ widely from each 

 other in appearance and composition ; that the Chillesford Clay being 

 a deposit remarkably sui generis, and easily recognizable, the sup- 

 position that the laminated bed is a local modification of it cannot 

 be admitted. In 1874, as I have observed, the section showed most 

 clearly the one bed resting on the other, as shown in fig. 1, which 

 is a copy of the sketch made at the time in my note-book. 



Moreover the paloeontological agrees with the physical evidence. 

 Wherever the sand and gravel at the base of the Chiilesford Clay, or 

 that Clay itself, yields molluscan remains, they are those of marine 

 species, except that in some localities a small admixture of fresh- 

 water forms imparts a slight fluvio-marine aspect to the formation. 

 In the gravel, however, which underlies the laminated bed in 

 question the mollusca are entirely of freshwater species, being prin- 

 cipally Unios with both valves united and clustered together nearly 

 as they lived. 



* These measurements are given on the authority of Mr. Henry Norton, F.G.S., 

 of Norwich, who spent several days in examining the section. 



t Mr. E. T. Dowson, of Geldeston, informs me that he has also found in it 

 the opercula of Bythinia tentaculata. 



\ The representation given in the sections may perhaps give the impression 

 that this thin and intermittent bed of sand is more regular than it really is. 



