THE IPSWICH MAN 213 
is an early Pleistocene deposit — upper or Runton beds, 
composed of laminated mud, loam, sanci, and vegetable 
debris, laid down in valley, estuary, and sea during 
many an alteration in the level of the land. Deeper 
still are the remains of an ancient submerged forest — the 
Cromer forest bed. Tree trunks, some of the stumps 
still rooted as they grew, make up the Cromer forest 
beds. These beds take us to the boundary line between 
the Pleistocene and the Pliocene. Sir Charles Lyell 
looked on them as representing a transition period. The 
plants and trees are those which are still familiar to us, 
but the mammals are of a kind which mark the fauna 
of the late Pliocene period. Three forms of elephants 
then lived in East Anglia — the predominant species 
being Elephas meridionalis. The modern roebuck and 
beaver were also there ; so were an ancient form of 
rhinoceros {R. etruscus), a large, extinct form of beaver 
{trogontheriuni). Lately, Mr A. C. Hinton has detected 
in these beds part of the arm bone of a monkey — 
belonging to a species very like the kind still living 
at Gibraltar. These deposits represent a long period of 
time. Sir Charles Lyell was of opinion that the interval 
between our time and the deposition of the 100-foot 
terrace was much shorter than that which lay between 
the terrace formation and the deposition of the Cromer 
beds. 
Having thus ascertained the position of the boulder 
clay among the deposits belonging to the .early part of 
the Pleistocene period, it is necessary to fill in some 
details bearing on its relationship to the 100-foot terrace 
of the Thames 'valley. Most geologists hold the opinion 
that the boulder clay is older than the 100-foot terrace 
because, at Hornchurch, in Essex, the valley terrace rests 
on the boulder clay. My friend, Mr A. S. Kennard, has 
called this opinion in question.^ He regards the 100- 
foot terrace as the older. Both views are probably right, 
for in the 100-foot terrace there are deposits of very 
different ages. In the deepest stratum of gravel of the 
' See Proc. Soc. Antiquaries, April 17th, 1913. 
