347 
and Freshwater Deposits of Eastern Norfolk. 
the sea has been continually encroaching on the cliffs, I found 
after an interval of ten years that a different section of the 
same beds was exhibited, and some difficulties cleared up 
which I had been unable to explain on my first visit. Never- 
theless a high beach precluded me at both periods from ob- 
taining a view of the lowest beds, which are sometimes ex- 
posed in winter at low water, and after storms. During my 
last visit in particular ( 1839 ) the prevalence of easterly gales 
prevented my seeing in some places no less than 12 feet in 
vertical height of the section which was visible in the summer 
of 1829 . 
The principal deposit which constitutes the mud cliffs of 
Eastern Norfolk is strictly analogous in character to that which 
has been called the “ boulder formation ” in Denmark and 
Sweden, and which, from the numerous erratics included in 
it, forms so remarkable a feature in the superficial geology of 
Scandinavia, and all the countries surrounding the Baltic, as 
well as northern Russia. It may be said to extend uninter- 
ruptedly from Sweden through the Danish islands, Holstein, 
and the countries of Hamburgh, Bremen, and Osnabruck, to 
the borders of Holland, and then to appear again with the 
same characters in Norfolk and Suffolk. Tiuoughout this 
tract, however, the average number and dimensions of the in- 
cluded erratic blocks, especially those of granite, porphyry, 
gneiss, and other crystalline rocks, diminishes sensibly on 
proceeding from north to south. 
As I am of opinion that the boulder formation in all these 
countries has been accumulated almost exclusively on ground 
permanently submerged beneath the waters, and that it does 
not consist of materials transported either by one or many 
transient rushes of water over land which had previously 
emerged, I shall dispense as far as possible with the term 
“ diluvium,” substituting that of “ drift ” for such portions 
of the deposit which cannot be proved to be fresh-water. 
Part of this drift consists of clay and loam wholly devoid of 
stratification, to which the name of“ till” may be applied, a 
provincial term widely used in Scotland for similar masses of 
unstratified matter, which there also contain most commonly 
included boulders. The entire want of a stratified arrange- 
ment in the till, whether in Scandinavia, Scotland, or Norfolk, 
implies some peculiarity in its mode of origin ; yet in all these 
countries some of the till has accumulated contemporaneously, 
and apparently in the same body of water, as much of the 
accompanying stratified gravel, sand, and clay. Moreover the 
stratified drifts are often identical in composition with the till, 
the distinction consisting merely in the mode of arrangement. 
