364. 
Mr. Lyell on the Boulder Formation^ 
var. of amnicum. The shell appears to be rather thicker than 
the recent P, amnicum^ and the teeth stronger : see fig. 1 1 . 
Fig. 11. 
Cyclas {Pisidium) amnica, var. ? 
From the freshwater beds at Runton. The two middle figures are of the natural 
size. 
Neither here nor at Miindesley was I able to find Cyrena 
trigonula^ which however we might have expected to discover 
in these beds, as it accompanies a similar assemblage of shells 
from various localities in Suffolk and Essex. 
I found no remains of insects in the black earth, but the 
Hon. and Rev. R. Wilson, of Ashwell Thorpe, showed me in 
his collection, in 1838, the elytra of beetles of the genus Do- 
nacia^ preserving their colours, which he had found several 
years before at Runton. I observed the scales of perch and 
of other fish resembling those of Mundesley in the black earth. 
Mr. Simons has also found fragments of the scapula and horns 
of a deer in the black earth. 
In general it is most difficult to speak with certainty re- 
specting the position of fossil bones of quadrupeds derived 
from the mud cliffs, because they have been picked up at the 
base of the cliff after portions of it had been washed away by 
the sea. It is the opinion, however, of collectors that they 
are chiefly derived from strata, in which the lignite and sub- 
merged trees occur. The remains are those of the elephant, 
rhinoceros, hippopotamus, horse, ox, pig, beaver, deer, &c. 
At Cromer and Weybourne some mammalian bones occur in 
the crag, but they are commonly more rolled and worn than 
those derived from the lignite deposits. Unfortunately no 
freshwater shells have yet been obtained from precisely the 
same bed as that in which the bones of the elephant and 
other extinct quadrupeds are met with, nor from the stratum 
in which the stools of buried trees are enveloped. The fresh- 
water shells of Mundesley and Runton, although they may 
probably belong to the same formation, are not yet proved to 
be strictly coeval with the extinct quadrupeds. The present 
state, therefore, of our knowledge would not enable us to enter 
into minute details in regard to the order of superposition of 
the beds between the chalk and drift in tlie mud cliffs, but it 
would appear that the principal site of the bones of extinct 
mammalia as well as of the buried forest and lignite is be- 
