206 



J. S. GARDNER ON THE LOWER LONDON TERTIARIES. 



feet of deep yellow slightly loamy sand, and then by quartzose sand 

 without green grains. At Oldhaven Gap the full thickness of the beds, 

 26 feet, is seen, the upper surface being very uneven and the fossils 

 casts only. The sands vary considerably in hardness, but at no par- 

 ticular levels. 250 yards west there are several small clay patches, 

 the thickest a foot deep. These are sharply denned above, but 

 below mix gradually with the sand, contain much selenite, and are 

 cemented into sandy concretions which display beautiful ripple- 

 marks and false-bedding. They are marked with horizontal borings 

 from one to one and a half inch wide. The clay patches frequently 

 rest on the pebbles, but are sometimes separated by drifts of broken 

 shells ; angular pieces of clay are occasionally included, and some- 

 times an indurated patch of lemon-coloured sand with iron-stains. 

 140 yards west the beds are 21 feet thick and very fossiliferous, with 

 green grains towards the base. A lenticular patch of clay with sandy 

 laminae, larger than usual, here encloses a Sarsen stone ; and on the 

 same horizon a few yards east are irony concretions crowded with 

 shells. 160 yards west the shells approach within 2 feet of the Lon- 

 don Clay, and there is much false-bedding ; and 90 yards further west 

 again a few concretionary blocks ore seen just above high water-mark. 

 The bedding of the sand is lenticular ; and the shells are almost com- 

 minuted, and also drifted into lenticular form, both the sand and 

 the shell-drifts being cut through again and again. A good section 

 is seen 500 feet before the beds dip under the London Clay (fig. 7). 



Fig. 7. — Section showing Junction of London Clay and Oldhaven 



Series. 



a. London Clay. b. Basement-bed. 



c. Sections across the ancient furrows of the shore. 



d. Broken shells deposited in furrows. 



The Oldhaven Beds sink under the London Clay at about a mile 

 east of Heme Bay. Their upper surface is eroded and filled in by 

 the basement-bed of the London Clay, here only from 12 to 18 inches 

 thick. The basement-bed is of a warm drab colour mottled with 



