o in describing those two
sections than to show how gradually they merge into one another. In
most rivers the passage of the upper waters is perfectly easy, and as
one descends the fords get rarer and rarer, until at last they cease.

With the Thames this is not the case. The two portions of the river
are sharply divided in the vicinity of Oxford, and that for reasons
which we have already seen when we were speaking of the suitability of
its banks for habitation. The upper Thames is indeed shallow and
narrow, and there are innumerable places above Oxford where it could
be crossed, so far as the volume of its waters was concerned. It was
crossed by husbandmen wherever a village or a farm stood upon its
banks. Perhaps the highest point at which it had to be crossed at one
chosen spot is to be discovered in the word Somer_ford_ Keynes, but
the ease with which the water itself could be traversed is apparent
rather in the absence than in the presence of names of this sort upon
the upper Thames. Shifford, for instance, which used to be spelt
Siford, may just as well have been named from the crossing of the
Great Brook as from the crossing of the Thames. The only other is
Duxford.

While, however, the upper Thames was thus easy to cross where
individuals only or small groups of cattle were concerned, the marshes
on either side always made it difficult for an army. The records of
early fighting are meagre, and often legendary, but such as they are
you do not find the upper Thames crossed and recrossed as are the
upper Severn or the upper Trent. There are two points of passage:
Cricklade and Oxford, nor can the passage from Oxford be made westward
over the marshes. It is confined to the ford going north and south.

Below Oxford, after the entry of the Cherwell, and from thence down to
a point not very easily determined, but which is perhaps best fixed at
Wallingford, the Thames is only passable at fixed crossings in
ordinary weather, as at Sandford, where the hard gravels approach the
bank upon either side, and at other places, each distant from the next
by long stretches of river.

It is not easy, now that the river has been locked, to determine
precisely where all these original crossings are to be found.

The records of Abingdon and its bridge make it certain that a
difficult ford existed here; the name "Burford" attached to the bridge
points to the ancient ford at this spot. It is a name to be discovered
in several oth