498 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 25, 
cene fauna and survived afterwards to bear a part in the Pliocene 
fauna, which is indicated by the Norfolk Hlephas meridionalis. An 
objection to this is found in the absence of the Mastodon from the 
forest-bed, and from all association with H. meridionalis in localities 
north of the Val d’Arno, 
3. The Mastodon arvernensis, certain species of Deer, and perhaps 
some other of the Mammalia, indicated by remains in parts of the 
Suffolk bone-bed, may be regarded as belonging to a later fauna 
than that to which the Trilophodont Mastodon (below described), the 
Rhinoceros Schleiermacheri, Tapirus priscus, and Hipparion belong. 
The M. arvernensis fauna may be supposed to have succeeded the ft. 
Schlecermachert fauna, and at the same time to have existed in Nor- 
folk, extending to a period later, probably, than the Coralline Crag ; 
whilst, at an earlier epoch, the Miocene mammals left their remains 
in the Diestien sands, which preceded the Crag, as is proved by the 
tooth of a Trilophodont Mastodon before mentioned. The condition 
of some teeth of Mastodon arvernensis from Suffolk, with their fangs 
preserved, tends to favour this view. The absence of Elephas from 
Suffolk, and its association in small proportion with the Mastodon in 
the Norfolk stone-bed, may be accounted for by granting what has 
been found to be true for France, namely that Hlephas meridinonalis 
did not coexist with Mastodon arvernensis. We may suppose that 
the #. meridionalis and Trogontherium of the Norfolk stone-bed 
lived after Mastodon arvernensis had passed away, belonging to a 
distinct fauna-period, that of the 1. meridionalis, fully represented 
in the forest-bed. Living on the lands which already contained 
remains of the Mastodon arvernensis in the silt of streams, in bogs, 
&c., these animals ultimately became associated with the past 
fauna in the Norfolk stone-bed. Thus we get three groups of ani- 
mals or faune, A, B, and C, associated by the breaking up of an old 
land surface. B left its remains in Suffolk, which already contained 
the remains of A, and in Norfolk, where A’s remains did not exist; 
C left its remains in Norfolk where B’s remains existed, but not in 
Suffolk, which had already the remains of A and B. A is the &. 
Schleermachert group, B the M. arvernensis group, and C the H. me- 
ridionalis group of mammals. 
The physical conditions indicated by the Diestien deposits in 
Suffolk, their absence from Norfolk, and the distribution of the later — 
deposits, are apparently such as would favour the separation of the 
Norfolk and Suffolk areas as required in the above hypothesis. 
Of the three hypotheses here offered I am inclined to the last, and 
though it is confessedly but a speculation, I submit that this ques- 
tion admits of a fair attempt at solution, and that we must not be 
content with the mere assertion that the bone-bed in Suffolk is a 
very heterogeneous assemblage of remains, and contains forms de- 
rived from the London clay as well as Mastodon. Hyracotherium and 
Coryphodon have only occurred altogether about six times in the 
nodules of clay from this bed; it is manifestly absurd, therefore, 
to speak of the London clay or Eocene beds as contributing largely 
to the mammalian fauna of the Suffolk Crag. 
