THE BLACKWATER ESTUARY.
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In the first place, its site is unusually lofty for this part of Essex, and
offers remarkable advantages for a fortified position both on that
account and the additional strength given by the river at the foot of
the hill. If we look at the possible sites for towns lower down the
estuary, we find that they consist of London Clay, or of low-lying
gravel or brick-earth, the alluvium of the marshes being, of course,
out of the question. And we may notice that in each case there is a
considerable breadth of marsh, or muddy foreshore, or of both,
between these sites and the main channel of the estuary. Now no
water supply could be obtained from the London Clay, while that to
be had from the low-lying gravel would probably be somewhat
brackish. In short, nowhere below Maldon is there anywhere on
the banks of the estuary a healthy and strong site for a fortified port.
But at Maldon all the advantages that could have been desired in the
site of an ancient town are singularly united. Besides its lofty and
strong position, it stands on a tongue of Glacial Drift overlying the
London Clay, and the water falling on the surface at Maldon, and for
a considerable distance westward of it, sinks through the more or less
permeable Drift, and is thrown out by the impermeable London Clay
beneath. Hence (as we learn from our programme) the existence of
the fine spring known as the "Cromwell Well," which still supplies the
town with water. Now, though an ancient town which nowadays
trusts solely to a shallow well supply shows a reckless disregard for
health, the existence of such a supply, in the days before deep wells
and water companies, had no small influence in determining the posi-
tion of habitations of all kinds. For want of knowledge of the
geology of Essex must have prevented any attempt to get water from
beneath the London Clay till quite recent times, and a supply from
the river must have been unattainable in times of siege.
In the next place we find that Maldon, in addition to special
advantages as a fortified town, possesses others as the site of a port
on the Blackwater Estuary. Higher up the separate channels of the
Chelmer and Blackwater are insignificant in size ; lower down, the
united channel must often have shifted its position in a way that would
have been highly disadvantageous, if not ruinous, to a port in that part
of the estuary. But at Maldon no very great lateral shifting can
have taken place, and it is probable that from a very early period
indeed, there has been a channel at the foot of the hill, between the
hill and the small patch of old river gravel on which the railway
station stands. The advantage given to a port by permanence in