THE 
LONDON AND EDINBURGH 
PHILOSOPHICAL MAGAZINE 
AND 
JOURNAL OF SCIENCE. 
[THIRD SERIES.] 
MAY 1840 . 
LVII. On the Boulder formation, or drift and associated 
Freshwater Deposits composing the Mud-cliffs of Eastern 
Norfolk. By Charles Lyell, V.P.G.S , F.R.S., ^c.^" 
^I^HE cliffs extending from Happisburgh or Hasborongh 
light-house to near Weybourne, north-west of Cromer, in 
Norfolk, comprising a distance of about 20 miles, are desig- 
nated in some maps as the mud-cliffs.” They are for the 
most part composed of deposits of two kinds, first, stratified 
and unstratified drift, called by some “ diluvium secondly, 
freshwater strata. Both of these rest on chalk, which is usually 
concealed below the level of the sea. Occasionally between the 
chalk and drift or the chalk and freshwater beds, a thin layer 
is found of marine crag, agreeing in its fossils with that of 
Norwich, but occurring only in patches of small extent, ex- 
cept near Weybourne, where it is more continuous. 
The drift, which sometimes attains a thickness of more than 
300 feet, consists principally of clay, loam, and sand, in some 
places stratified, in others wholly devoid of stratification. 
Pebbles, and in some places large boulders of granite, por- 
phyry, greenstone, lias, chalk, and other transported rocks are 
interspersed, especially in the unstratified portion. Pure and 
unmixed white chalk rubble, and even huge fragments of so- 
lid chalk, are also associated in some localities. No fossils have 
been detected in this drift which can positively be referred to 
the aera of its accumulation ; but besides the organic remains 
derived from secondary strata, it contains almost everywhere 
broken fragments of shells which agree in species with those 
of the Norwich crag, from which there is good reason to be- 
lieve them to have been washed out. 
* Communicated by the Author. 
Phil. Mag. S. 3. Vol. 16. No. 104. May 1840. 2 A 
