174 
at the bottom of the drift and immediately upon the chalk or crag. 
They are most largely developed at Mundesley and Runton, under- 
lying the drift at the latter locality, and partly cotemporaneous with 
it and partly superimposed upon it, at the former. The shells con- 
tained in the deposits are with few exceptions existing British 
species ; and Mr. Lyell consequently infers that the entire forma- 
tions of the mud cliffs, both freshwater and drift, belongs either to 
the latest period of the newer pliocene tertiary era, or to the post 
tertiary period. Hasborough has been long celebrated as one of the 
principal submarine forests of East Norfolk; and Mr. Lyell quotes 
the description by Mr. R. C. Taylor respecting the deposits gene- 
rally. (See Geol. of Norfolk, pp.’7 and 23.) He has not seen the 
stools of the trees in situ, owing to the state of the beach during 
his visits, but he has no doubt of their existence, from the testimony 
of independent witnesses, particularly of Mr. Simons of Cromer. 
During the winter of 1838-1839, a bed of lignite centaining bones 
of Elephants, pieces of wood, and roots of trees 2m situ, was exposed 
at Woolcot Gap, between Hasborough and Bacton, by the removal of 
a mass of incumbent drift thirty feet thick. At this point, therefore, 
the lignite bed was ascertained clearly to underlie the drift; and at 
other localities, the same extension inland has been proved by simi- 
lar destructions of the cliffs; Mr. Lyell consequently observes, that 
after the chalk, previously covered in part at least with Norwich erag, 
had been overspread with layers of sand and clay, the surface was 
converted into dry land, on which forest trees grew; that the sur- 
face was again submerged, the trees broken off near their roots, and 
gradually buried, with their branches, leaves, and occasionally bones 
of land animals, beneath the drift. ‘The following details are given 
of the points which more particularly engaged the author’s attention. 
Munpestey. North and south of this town, tlie cliffs vary in height 
from forty to seventy feet, and consist in their lower part of blue 
clay or till covered with stratified yellow sand and loam; but at 
Mundesley the cliff is only twenty or thirty feet high, and is occu- 
pied for several hundred yards by a freshwater deposit covered with 
about ten feet of flint gravel. The freshwater beds are irregular in 
extent, and consist of brown, black and gray sand and loam mixed 
with vegetable matter, sometimes almost passing into a kind of peat 
containing much pyrites. A few layers of rounded flint pebbles 
are interspersed in the mass. The bottom of the deposit was not 
visible ; but Mr. Lyell is of opinion, that it is not much below the 
level of the sea, Mr. Simons having seen chalk zm situ at Mundesley 
at low water. In 1829 a mass of till was prolonged into the fresh- 
water beds at their southern junction with the drift'in such a man- 
ner as to imply the contemporaneous origin of the lower part, at 
least, of both formations. The interpolation of this freshwater ac- 
cumulation, Mr. Lyell conceives, may have been effected by a small 
river flowing through the banks of drift during the subsidence of 
the cliffs, and depositing its earthy contents, with the drift wood 
and other transported materials. The shells obtained by the author, 
Mr. Fitch of Norwich, and Mr. J. B. Wigham, are Paludina impura, 
