130 THE ESSEX NATURALIST.
values in the south-western London Clay area were very low
indeed.
By 1412 a.d. the parish assessments were definitely higher
in the Boulder Clay region, although some very low assessments
occurred. In 1638 a.d. practically all the Boulder Clay parishes
showed a higher assessment than any of the London Clay parishes;
the light soil parishes occupying an intermediate position.
From the increasing value of the Boulder Clay parishes we
may assume that the clearing of the Boulder Clay forest pro-
ceeded apace during mediaeval times and by 1638 it is exceedingly
doubtful whether much woodland remained on this fertile area.
It is interesting to compare these assessment maps with the Land
Utilisation map of the same area for 1933. The Boulder Clay
district and most of the light soil areas now appear as the main
arable land; the London Clay carrying grassland.
The position of the chief areas of the rapidly vanishing
Forest during this mediaeval period may be deduced with some
accuracy from the presence of moated houses in certain areas
of the county. Many houses of some age appear in Essex and
other counties, in which the moat seems to fulfil no defensive
purpose with regard to the house. Many examples could be
quoted where the moat does not entirely encircle the house,
but only partially so, often enclosing a piece of ground adjoining
the house. In some instances the moat is almost detached from
the building, and cases occur in which the moat is entirely
removed from the house and situated some yards off, encircling
a fair-sized piece of ground.
Many of the houses bearing such moats are to be found
referred to in charters of late mediaeval times.
The great majority of such houses occur to the north-west
within the Boulder Clay area, a few examples appearing within
those eastern areas seen to be wooded in Norman times such as
Hockley, Tiptree and Danbury. Still others are situated to the
south-west of the county.
The peculiar position of such moats, and their distribution
throughout the County, seems to indicate a function incompatible
with any defence of human life. To-day the enclosed land
surrounded by these moats is usually an orchard or vegetable
garden, and it seems not improbable that it existed as such
in mediaeval times. The moat may have acted as a defence