From one or other of these causes many English rivers on which considerable traffic formerly passed have dwindled in importance, even if they have not ceased to be navigable at all; and many inland places that once flourished as river, or even as "sea"-ports, would to-day hardly be regarded in that light at all, as shown, for example, by the fate of Lewes on the Sussex Ouse, Deeping on the Welland, Cambridge on the Cam, Ely on the Ouse, West Dean on the Cuckmere, and Bawtry on the Idle. York and Doncaster, though situated so far inland, once considered themselves seaports because of their river connection with the coast, so that, as told by the Rev. W. Denton, in "England in the Fifteenth Century," they claimed and exercised the right of sharing in "wrecks at sea" as though they stood on the seaboard instead of high up the course of the Ouse or the Don. The Romans not only supplemented their road transport by river transport but they sought to improve the latter by the construction of river embankments. In the case of the Trent and the Witham they even cut a canal--the Fossdyke--in order to establish direct communication between them. Just, however, as road-making became a lost art here on their departure from Britain, so did an interval of a thousand years elapse before there was any material attempt to follow their example in effecting improvements in river navigation. The {112}initial advantage, therefore, lay with towns located on rivers which were naturally navigable and remained navigable both for a considerable extent and for a considerable period, without need of amendment; though river navigation, as a whole, did not attain to its highest development until, as will be shown in the chapter that follows, much had been done, especially in connection with streams not naturally navigable, to overcome the various impediments or difficulties to effective transport. All the same, the part that English navigable rivers, great or small, have played in the social and economic progress of the country has been one of undeniable magnitude and importance, and offers many points of general interest. These considerations more especially apply to the river Severn, which, in conjunction with such of its tributaries as the Wye and the Warwickshire Avon, was once the great highway for the trade and traffic, not only of the western counties, but of, also, a considerable area in Wales and the midland and northern counties, enabling the districts it more directly served to attain an early development long before others which were then still struggling with the disadvantages of bad roads, however much they may since have outstripped them in the race for industrial advancement.