and FresMmter Deposits of Eastcv7i No? folk. S75 
name of Black Meg. This collection extends about two 
miles, chiefly opposite to Beeston Hill*. 
The author just cited truly remarks, that this singular as- 
semblage of boulders must have been dislodged from the 
wasting cliffs, of which the softer and finer materials have 
been removed by currents, for similar boulders are occasion- 
ally observed in the midst of the clay or till of the cliffs. 
In different parts of the interior of Norfolk, boulders weigh- 
ing several tons have been found in blue clay or tillf. 
I stated in the first edition of my Principles of Geology 
that 1 was unable in 1829 to draw a line of demarcation be- 
tween the crag and the drift or diluvium. The Rev. W. B. 
Clarke afterwards insisted on the distinctness of the two for- 
mations +, in which opinion I now concur, although I am 
still unable, in many spots, as, for example, near Weybourne, 
and between Southwold and Yarmouth, to say where the crag 
ends and the stratified drift begins. But this difficulty arises 
from the absence of fossils in the crag as well as the drift, and 
from the fact that the strata in the latter are often as regular 
and continuous for considerable distances as those of the 
crag. 
Professor Sedgwick informs me, that in the unstratified 
brown clay or till of certain parts of Cambridgeshire, large 
angular blocks of lower green sand and chalk, with fossils of 
the Oxford clay and lias, occur. The till alluded to attains 
at some points a thickness of 300 feet: it resembles that in the 
Norfolk mud cliffs, and has been traced over many of the ad- 
joining counties. Its extent therefore in area and depth ren- 
der its history of high importance in the geology of the east 
of England. 
I mentioned in the beginning of this paper, that I recog- 
nized the strongest resemblance between the boulder forma- 
tion which I have seen in Sweden, Denmark, Holstein, and 
other countries, and the drift of Norfolk ; and as I believe 
coast-ice and icebergs to have been instrumental in trans- 
porting much of the large and small detritus in Scandinavia, 
so I presume that at the same period the effects of the same 
agency was extended to the British seas, although on a 
smaller scale. But while some of the Norfolk erratics may 
be of northern origin, other portions of the associated drift 
may have been brought from neighbouring regions, and per- 
haps in an opposite direction, just as we now observe that 
* Geology of East Norfolk, p. 24 , 1827- 
t C. B. Rose, Geology of West Norfolk, bond, and Edin. Phil. Mag , 
January 1836, p. 195. 
% Geol. Trans., 2nd Series, vol. v., part 2, p. 363. 
