164 
CKOMEK rOREST-BED. 
recent alluvium, and may originate in various ways. An elephant, 
hippopotamus, or other large animal treading in the shallow 
water would easily s jueeze the clays into these shapes. One 
may notice that the oxen and horses standing on the shores of 
the Broads often force up black mud through the gravel on each 
side of their footprints. Another mode of accounting for the 
contortion is that it is due to the lateral thrust caused by the 
alternate freezing and thawing of the beds in the winter. But 
in either case it is noticeable that in the well-laminated fresh¬ 
water clays that are found at Sidestrand and a few other places, 
and which appear to have been formed in water too deep for 
freezing, or disturbance by the growth of water-plants, no con¬ 
tortions are found. In the contorted beds the common mollusca 
are the almost amphibious Succinea, Limncea peregra {L. 
limosa), and Pisidium piisillum, while in the bedded clay of 
Sidestrand the more lacustrine A (Velletia) lacustris is 
perhaps the most abundant species. 
The Lower Freshwater Bed is now cut out, but for a quarter 
of a mile to the south-east, beyond slight variations in the 
relative thickness of the different deposits, there is no other 
change and the small roots can be seen about 8 feet above the 
beach wherever the section is free from talus. At about three 
furlongs south-east of the old groyne at Trimingham the three 
tree stumps shown in Fig. 36, p. 151, were found. The section 
is:— 
Boulder Cla 3 ^ 
Upper Fresh¬ 
water Bed. 
Forest-bed 
(estuarine). 
/ False-bedded sand, with irregular seams of 
\ grey loam and a gravelly base 
^False-bedded sand, with a few seams of loam 
and scattered pebbles - . . 
Laminated and false-bedded sand and clay - 
; (Strata hidden by beach) . - - 
1 Clay-pebbles and pan, with tree-stumps and 
lignite - - - - - 
Blue laminated carbonaceous clay, lignite, 
and clay pebbles 
Feet. 
2 
1 ^- 
4 
2 
3 + 
About 200 yards further south, the bed of clay-pebbles which 
contains the tree-stumps yielded a jaw of cod, the only marine 
fossil noticed in the Forest-bed in this neighbourhood, except a 
tooth of the sperm whale {Physeter macrocephalus). 
The false-bedded sands now gradually change to laminated 
clay, which forms a conspicuous mass 6 feet thick at the base of 
the cliff under Trimingham lirne-kiln. About 50 yards further 
south tl)e mass of laminated clay has been cut out and replaced 
by sand and loam. Then the Boulder Clay gradually descends 
and cuts out the Freshwater Bed, but the Estuarine division 
can be traced to near the western Chalk bluff at Trimingham. 
There are continual variations, but it is unnecessary to note 
every change. The last section which could be seen was 80 yards 
from the Chalk. Unfortunately persistent talus prevents us 
from tracing the beds till they disappear in the glacial contortion 
