369 
and Freshwate7' Deposits of Eastern Nojfolk, 
that of Old Hythe point (fig. 13.). It will sometimes happen, 
however, that the enveloping beds of drift appear to be folded 
completely round a nucleus of chalk or sand, or any other ma- 
terial found in the mud cliffs as in the annexed cut (fig. 15.) 
or in fig. 1 6, which represents a perpendicular cliff 20 feet high, 
in which the beds are: 1. blue clay; 2. white sand in thin 
layers ; 3. yellow sand ; 4-. striped loam and clay ; 5. laminated 
blue clay; and I saw curves not far from this place which ex- 
tended fora vertical height of 50 feet, in which SOdistinct strata, 
without counting the subordinate laminae, in all 24- feet thick, 
presented the same concentric arrangement. The beds con- 
sisted alternately of blue clay and white sand, the bed of sand 
exposed in the centre being blackened by bituminous matter. 
I have mentioned some of these cases of the apparent fold- 
ing of the beds round a central nucleus in the Principles of 
Geology, especially one which occurs in the cliffs east of 
Sherringham, where a heap of partially rounded flints about 
five feet in diameter appears nearly enveloped by finely la- 
minated strata of sand and loam, in the midst of which again 
is a nucleus of loam. After a more scrupulous examination 
of many of these cases, I have now ascertained that they are 
all, without exception, examples of the intersection of a series 
of strata which have been bent into a convex form, the appa- 
rent nucleus being in fact the innermost bed of the series, 
which has become partially visible by the entire removal of 
the protuberant part of the outer layers. 
I observed a portion of a cliff 8 feet in vertical height be- 
tween Beaston Hill and East Runton, in which a nucleus of 
very loose sand 18 inches in diameter [a) was surrounded 
by layers of clay and loam as represented in fig. 17. The 
vertical beds on the left side of the cut consisted of similar 
incoherent materials, some of the seams of sand being charac- 
Fig. 15. 
Fig. 16. 
Section of concentric beds west of Cromer. 
