ally bounded by rivers. Thus the Thames divides counties along
nearly its whole length, forming the southern boundary of four and the
northern boundary of three. Essex and Suffolk, Suffolk and Norfolk,
Cornwall and Devon, Durham and Yorkshire, Lancashire and Cheshire, are
all separated by rivers, while rivers form some part of the boundaries
of almost every county. Still, it is noteworthy that the Severn and
Trent nowhere form continuous county boundaries. Watersheds are rarely
used as boundaries for any distance; but, although slightly
overlapping the watershed on all sides, Yorkshire is very nearly
coincident with the basin of the Ouse. The boundaries of the parishes,
the fundamental units of English political geography, are very often
either rivers or watersheds, and they frequently show a close relation
to the strike of the geological strata. The hundreds, or groups of
parishes, necessarily share their boundaries, and groups of hundreds
are often aggregated to form larger subdivisions of counties. A wider
grouping according to natural characteristics may now be recognized
only in the cases of Wales, East Anglia, Wessex and such less definite
groups as the Home Counties around London or the Midlands around
Birmingham. Configuration is only one out of many conditions modifying
distributions, and its effects on England as a whole appear to be
suggestive rather than determinative. (H. R. M.)

III. GEOLOGY

For an area so small, England is peculiarly rich in geological interest.
This is due in some degree to the energy of the early British
geologists, whose work profoundly influenced all subsequent thought in
the science, as may be seen by the general acceptation of so many of the
English stratigraphical terms; but the natural conditions were such as
to call forth and to stimulate this energy in an unusual way. Almost
every one of the principal geological formations may be studied in
England with comparative ease.

If we lay aside for the moment all the minor irregularities, we find,
upon examination of a geological map of England, two structural
features of outstanding importance. (1) The first is the great
anticline of the Pennine Hills which dominates the northern half of
England from the Scottish border to Derby. Its central core of Lower
Carboniferous rock is broadly displayed towards the north, while
southward it contracts; on either side lie the younger