The basement beds of the Turbiferous or Newer Alluvial Fen Beds are
clearly separated by their stratification from the Areniferous or Older
Alluvial Terrace Beds down the sloping margin of which they creep, but
there is not anywhere, as far as I am aware, any passage or dovetailing
of the Fen Beds into the gravel of the river terraces, while the
difference in the fauna is very marked.
It is however from such sections as those just described that the
erroneous view arose that the Elephant and Rhinoceros occurred in the
older Fen Beds. It is true that they have been found under peat in the
Fenland, but that is only where the gravel spurs of the Old Alluvial
Terraces or Areniferous Series have passed under the newer Fen Beds.
I saw the remains of _Rhinoceros tichorhinus_ in the gravel beds
belonging to the older or Areniferous Series at Little Downham, and
from the base of the gravel in the Whittlesea brickpit I obtained a
fine lower molar of _Elephas antiquus_. This was, however, not in
the Gravel, but squeezed into the soft surface of the underlying
Jurassic Clay.
There have never been any remains of Elephant or Rhinoceros found in
the Turbiferous series.