PRIMITIVE MAMMALS IN THE LONDON CLAY OF HARWICH. 99
skeletons, subsequently met with in the Lower Eocene of North
America, have nearly completed our knowledge of the animal.
It now appears that Coryphodon is not closely related to the
tapir or any other existing quadruped, but that it belongs to a
lowly group of hoofed animals which had a much smaller and
simpler brain than any existing hoofed quadruped. The ends of
the ridges on its teeth are "peaked" because these teeth are
directly derived from those of ancestors which had teeth with
high pointed cusps. The five-toed feet are less well adapted
for supporting a heavy body when walking than those even of
an elephant. Coryphodon, indeed, was a precocious overgrown
member of a primitive group of hoofed quadrupeds (Amblypoda)
which included the ancestors of several modern groups. It soon
died out in Europe, but it was succeeded in the Middle and
Upper Eocene in North America by the still larger small-brained
quadrupeds with horns, which Marsh named Dinoceraia.
The second discovery of a fossil mammal in the London Clay
near Harwich, in 1857, was still more important than that of
Coryphadon. Nearly twenty years previously Owen had already
described part of a skull with teeth from the London Clay of
Herne Bay, Kent, under the name of Hyracotherium,5 and his
ultimate conclusion6 was that "the form and structure of the
molar teeth determined this interesting extinct genus to belong
to the same natural family of the Hog tribe as the Choeropo-
tamus." The new specimen, obtained by the Rev. Richard Bull
from a Septarian nodule in the cement workings near Harwich,
comprised not only the almost complete skull and lower jaw of
a similar mammal, but also a humerus, femur, and three metatarsal
bones, besides other fragments of the skeleton. The remains
were extricated from the hard matrix by Mr. Dew, of the British
Museum, and a fragment was sawn out of the left side of the skull
to expose the crowns of the upper and lower teeth. This frag-
ment was kept by the British Museum but the rest of the specimen
was returned to Mr. Bull, and after his death was long supposed
to have been lost. A few years ago, however, his widow, Mrs.
Bull, offered the remains to the British Museum (Nat. Hist.),
and there the whole specimen is now preserved. The skull in
its present state is shown in a series of photographs in Plate XII.
5 R. Owen, Proc. Geol. Soc., vol., iii. (1840), p. 162 ; Trans. Geol. Soc., ser. 2, vol. vi,
(1841), pp. 203, 211, pl. xxi., figs. 1-4.
6 R. Owen, British Fossil Mammals and Birds, 1846, p. 423.