Long after the passing of the Act of 1691, and perhaps in consequence of it, the causeway formed an important feature of the roads. This causeway, or bridle-track, ran down the middle; while the margin on either side was little better than a ditch, and being lower than the adjoining soil, and at the same time soft and unmade, received and retained the sludge. But, in truth, the state of the roads concerned the Post Office far less at the close of the seventeenth century than it did at the close of the eighteenth. The mails were carried on horseback; and, even so, they were carried mainly over the six great roads of the kingdom. These roads, as compared with others, were good; and execrably bad as we might now think them, they were probably not altogether ill adapted to riding. The disasters which history refers to this period, as illustrating the difficulties of travelling, occurred generally on the cross-roads, and always with wheel traffic. For both wheel traffic and horse traffic the six great roads had, probably from the earliest times, been kept in some sort of repair. On the great Kent Road, nearly a hundred years before, a young Dane, with his attendants, had on horseback accomplished the distance between Dover and London in a single day.[17] In 1642 couriers had ridden from London to York and back, a distance of about 400 miles, in thirty-four hours,[18] a feat barely possible except on the assumption that the road was in tolerable order. Now and again, indeed, some postmaster, pleading for the remission of his debt to the Crown, would urge the losses he had sustained in horse-flesh by reason of the badness of the roads; but these roads were always cross-roads--roads along which, if he had delivered letters, he had delivered them on his own account. Of the six great roads as a means of transit for the mails there were no complaints. [17] The Forty-Sixth Annual Report of the Deputy-Keeper of the Public Records, Appendix ii. p. 69. [18] _Clarendon's Life_, vol. i. p. 135.