296 ON THE ZONAL STRATIFICATION OF THE
most of the Crag Echinoids are of extinct species, all the Crus-
tacea are still living in British waters.
The closer the various areas and contents of the Crags are
scrutinised, the more students will, like myself, be disposed
to agree with Mr. Harmer's contention that the various Pliocene
beds in East Anglia represent stages of a more or less connected
and continuous period, during which, however, important
tectonic changes took place ; and the southern fauna becoming
gradually eliminated, being replaced by those of a more boreal
type.
The researches of Mr. Harmer at Little Oakley, near Dover-
court, have shown that the break between the Coralline and Red
Crags is of less importance than has been supposed—and as
bridging over this break or gap, I propose instituting a sub-zone or
Upper Division of the Gedgravian Crag, which I term Boytonian,
from Boyton, near the Butley River, where it was exposed
when Coprolite digging was at its height, a zone linking on
the Coralline to the oldest of the Red Crag deposits. As so
little is known of it, and it is rather inaccessible, I may briefly
refer to the section from personal observation at the time of
working, and from information given me by an old Coprolite
worker in the pit.
This pit was opened in low ground near the Butley Marshes,
and as it was flooded by percolating waters, the men worked in
thigh boots, washing the Coprolite-bearing material in the
pond they stood in. The ground or surface soil was first re-
moved, then the Red Crag, down to the Coprolite, which was
picked by hand, but not washed. Below this was a bed of
white Crag, full of shells, only a few inches thick, resting upon a
lower vein of Coprolite debris, the two being washed together
as just referred to. The stuff not proving payable, the pit was
soon abandoned. Some of the workmen, while the section was
open, gathered a quantity of the fossils, and from boxes of the
material that passed through my brother's hands or mine, and
also from other sources, I have been able to complete the lists
of species from this locality here given for the first time.
The reason that led me to propose this as a separate and
upper zone of the Coralline Crag is the number of Red Crag
species not hitherto recorded as Coralline Crag shells, or if
recorded, being very rare, associated with species as equally