THK 1'I.IOCKNE SERIES 593 





the sea. They were first desc-rilx-d l>y IVni'i -MI- l'n-t \\ich in 1857, 

 ami more fully explored by Mr. ('. Reid in 1886. 13 The Leuham 

 Beds are mere remnants of a deposit which must originally have 

 had a wide extension, not only in England but eastward through 

 Belgium. These remnant- have been preserved because they have 

 subsided into deep pipes and hollows caused by the solution of the 

 underlying Chalk. The hollows are lined with brown clay full 

 of unworn flints, and these clay walls enclose a set of sandy deposits, 

 yellow and red sands, reddish fossiliferous sandy ironstone, and 

 greenish sand with scattered flint pebble*. 



From these beds, and chiefly from the ironstone, Mr. C. Reid 

 obtained sixty-seven species of Mollusca, and all but fifteen 

 have been found in the Coralline Crag, so that there cannot be 

 much difference in their relative age in spite of the great difference 

 in relative level. There are, however, some species which do not 

 ori-ur in the Coralline Crag, but are found in the older Pliocene or 

 later Miocene Beds of Europe ; these are Area diluvii, Cardium 

 papillosum, Terebra acuminata, Pleurotoma consobrina, P. Jouanneti, 

 the first t wo shells being very abundant. On the whole, therefore, 

 the Lenham Crag is probably older than the Coralline, and Mr. 

 F. W. Harmer thinks that it was considerably older. 13 



Some patches of similar sand occur farther on the Surrey 

 downs, but no recognisable fossils have yet been found in 

 them, and it is consequently uncertain whether they are of the 

 same age. 



The nodule bed at the base of the Suffolk Crags contains many 

 rounded lumps of tough brownish sandstone which are known as 

 hoxstones, and have evidently been derived from an older deposit. 

 Many of these contain fossils, and some of them are species which 

 occur in the Coralline Crag, but two are only known from the 

 older Pliocene of the continent ; these are Conus Dujardini and 

 Valuta auris-leporis. 



Coralline Crag. This crag is only found over a small area 

 in Suffolk between Aldeburgh and Boyton, and in three other 

 small isolated patches at Sutton, Ramsholt, and Tattiugstone (see 

 map, Fig. 198). It rests on an eroded surface of the London Clay, 

 and its basement-bed (as seen at Sutton) contains a remarkable 

 a-.-emblage of materials derived from older deposits, and chiefly 

 from the London Clay ; the pebbles are chiefly phosphate nodules 

 of a dark-brown colour, but with these are fragments of septaria > 

 a few small pebbles of quartz and flint, and the boxstones which 

 have l>een mentioned above ; there are also Crustacea and fish 

 teeth derived from the London Clay, reptilian vertebra; from the 

 Oxford Clay, mammalian teeth of doubtful age, many Cetacean 



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