A few miles below Abingdon is Dorchester (not to be confused with the Dorset town of the same name), not exactly on the River, but about a mile up the tributary river, the Thame, which here comes wandering through the meadows to join the main stream. Like Abingdon, Dorchester has had its day, but its abbey church remains, built on the site of the ancient and extremely important Saxon cathedral; and, one must confess, it seems strangely out of place in such a sleepy little village.
Wallingford, even more than these, has lost its ancient prestige, for it was through several centuries a great stronghold and a royal residence. We have only to look at the map of the Thames Valley, and note how the various roads converge on this particularly useful ford, to see immediately Wallingford’s importance from a military and a commercial point of view. A powerful castle to guard such a valuable key to the midlands, or the south-west, was inevitable.
William the Conqueror, passing that way in order that he might discover a suitable crossing, and so get round to the north of London (p. 143), was shown the ford by one Wygod, the ruling thane of the district; and naturally William realized at once the possibilities of the place. A powerful castle soon arose in place of the old earthworks, and this castle lasted on till the Civil War, figuring frequently in the many struggles that occurred during the next three or four hundred years.
It played an important part in that prolonged and bitter struggle between Stephen and the Empress Maud, and suffered a very long siege. Again, in 1646, at the time of the Civil War, it was beset for sixty-five days by the Parliamentary armies; and, after a gallant stand by the Royalist garrison, was practically destroyed by Fairfax, who saw fit to blow it up. So that now very little stands: just a few crumbling walls and one window incorporated in the fabric of a private residence.
Between Wallingford and Reading lies what is, from the geographical point of view, one of the most interesting places in the whole length of the Thames Valley—Goring Gap.
You will see from a contour map that the Thames Basin, generally speaking, is a hill-encircled valley with gently undulating ground, except in the one place where the Marlborough-Chiltern range of chalk hills sweep right across the valley.
By the time the River reaches Goring Gap it has fallen from a height of about six hundred feet above sea-level to a height of about one hundred feet above sea-level; and there rises from the river on each side a steep slope four or five hundred feet high—Streatley Hill on the Berkshire side and Goring Heath on the Oxfordshire side.
The question arises, Why should these two ranges of hills, the Marlborough Downs and the Chiltern Hills, meet just at this point? Is it simply an accident of geography that their two ends stand exactly face to face on opposite sides of the Thames?
Now the geologists tell us that it is no coincidence. They have studied the strata—that is, the different layers of the materials forming the hills—and they find that the strata of the range on the Berkshire side compare exactly with the strata of the other; so that at some remote period the two must have been joined to form one unbroken range. How then did the gap come? Was it due to a cracking of the hill—a double crack with the earth slipping down in between, as has sometimes happened in the past? Here again the geologists tells us, No. Moreover they tell us that undoubtedly the River has cut its way right through the chalk hills.