er parts of England where there has been some ancient
crossing of a river, as, for instance, the crossing of the Mole in
Surrey by the Roman military road.

The next place below Abingdon may have been at Appleford, but was more
likely between the high cliff at Clifton-Hampden and the high and dry
spit of Long Wittenham. Below this again for miles there was no easy
crossing of the river.

The Thames was certainly impassable at Dorchester. The whole
importance of Dorchester indeed in history lies in its being a strong
fortified position, and it depends for its defence upon the depth of
the river, which swirls round the peninsula occupied by the camp.

It has been conjectured that there was a Roman ford or ferry at the
east end of Little Wittenham Wood, where it touches the river. The
conjecture is ill supported. No track leads to this spot from the
south, and close by is an undoubted ford where now stands Shillingford
Bridge.

Below this again there was no crossing until one got to Wallingford;
and here we reach a point of the greatest importance in the history of
the Thames and of England.

Wallingford was not the lowest point at which the Thames could ever be
crossed. So far was this from being the case that the _tidal_ Thames
could be crossed in several places on the ebb, notably at the passage
between Ealing and Kew, where Kew Bridge now stands; and, as we shall
see, the Thames was passable at many other places. But the special
character of the passage at Wallingford lay in the fact that it was a
ford upon which one could always depend. Below Wallingford the
crossings were either only to be effected in very dry seasons or,
though normally usable, might be interrupted by rain.

It is at Wallingford, therefore, that the main lowest passage of the
Thames was effected, and it was through Wallingford that Berkshire
communicated with the Chilterns. Wallingford is, then, the second
point of division upon the Thames when one is regarding that river as
a defence or a boundary. Below Wallingford there was perhaps a regular
crossing at Pangbourne; there was certainly a ford of great importance
between Streatley and Goring; and all the way down the river at
intervals were difficult but practicable passages--notably at Cowey
Stakes between the Surrey and the Middlesex shore, a place which is
the traditional crossing of Caesar. The water here in normal weather
was, however, as much as five feet deep, and this ford well
illu