ON THE UPPER CLAY OF WALTON NAZE. 223
Lamium purpurum, var. decipiens, Sonder. Near Frinton.
Atriplex hastata, L. Near Frinton.
,, angustifolia, Sm. Near Frinton.
,, laciniata, L. Near Frinton.
,, babingtonii, Woods. Near Frinton,
,, littoralis, L., and var. marina, L. Near Frinton.
Chenopodium paganum, Reich. Near Frinton.
Polygonum aviculare, L., var. rurivagum, Jord., var. micro-
spermum, Jord., and var. arenastrum, Boreau. Near Frinton.
Scirpus tabernaemontani, Gmel. Near Frinton.
Avena fatua, b. intermedia, Lindgr. Near Frinton.
Sclerochloa distans, Wahlb. Near Frinton.
ON THE UPPER CLAY OF WALTON NAZE.
By W. H. DALTON, F.G.S.
[Read September 14th, 1889.]
Much as has been written on the interesting section afforded by the
cliff of Walton Naze, there is one point of considerable interest
therein which still remains to be solved, and that is the age of the
beds which overlie the Crag.
The bulk of the literature of the subject 1 refers naturally to the
Crag, the London Clay offering no features of interest, except from
the point of view of the student of denudation. The clay which
forms the subject of the present note offers to the palaeontologist
only obscure fragments of wood from a peaty seam, which occurs
about the middle of its small thickness. It lies with marked uncon-
formity on the Crag, overlapping it at one or two points so as to rest
directly on the London Clay. From its lithological character, a fine
grey clay, it has been always regarded as Chillesford Clay, and is so
spoken of in every account of the section that mentions it at all.
Its unconformability with the Crag, as contrasting with the passage
between the two that obtains at Chillesford and elsewhere, was
readily accounted for by Mr. S. V. Wood, who pointed out 2 that the
Crag of this district contains a slightly older congeries of fossils than
that of Suffolk, and may have been formed under somewhat different
conditions nearer the beginning of the Red Crag period than that
1 See the "List of Works on the Geology of Essex," pp. 61— 86 of this volume.
2 "Quart: Journ : Geol: Soc: vol. xxii. p. 541 [1866].