S58 
Mr. Lyell o?i the Boulder Formation^ 
the wall of chalk are vertical, (see diagram, fig. 8.) yet the 
beds of the same formation have but a moderate inclination 
Fig. 7. 
Northern protuberance of chalk, Trimmingham. 
a. Chalk with flints. 
h. Gravel of broken and half-rounded flints. 
c. Laminated blue clay. 
in the lofty cliff behind. A layer of chalk flints in situ shows 
that the stratification of the chalk itself is nearly vertical at 
least in one place, although the beds seen in a large cave facing 
the sea show a slight curvature only. Where the chalk joins 
the drift on the southern or Mundesley side of the promontory, 
I observed in 1839, at the junction, 1st, a portion of the chalk 
itself decomposed, then a vertical bed of gravel, (g, fig. 8) 
30 feet high and several feet thick, then dark blue clay with 
white chalk pebbles, then sandy, and then other beds of or- 
dinary drift. Some of these disturbed beds contain fragments 
Fig. 8. 
drift. 
g. gravel. 
chalk. 
sea. 
of marine crag shells, as C/jprina^ Cardium^ Tellina^ &c. I 
have stated in the Principles* that this mass of chalk at its 
northern edge, or towards Trimmingham, actually overlies 
some beds of blue clay or drift as at the right hand extremity 
of fig. 7. Now this remarkable superposition was still evident 
in June 1839, notwithstanding the unusual height of the sea 
* Vol. iii. p. 180, 1st edit., and vol. iv. p. 8C, flth edit. 
