[Illustration: FIG. 2. PLAN OF ROMAN WALLS, ETC., AT GARIANNONUM (BURGH CASTLE) (From an engraving published in 1776)] The masonry is of the kind which is usually found in Roman buildings, namely, a rubble core with courses of bonding tiles, and an outer facing of flints chipped to a flat surface. Gariannonum was a place of great importance in Roman times. Here was stationed the captain of the Stablesian horse, styled Gariannonensis, under the command of _Comes littoris Saxonici_. _Walton._--Near Felixstow, situated on what is now the fore-shore, but which originally was a cliff 100 feet high, and commanding extensive views of the surrounding country, are the ruins of what was an important Roman station. Although possibly not ranking as one of the nine great coast fortresses, it occupied a most important site for the defence of this part of the east coast of Britain, and commanded not only the entrance to the River Deben, but also all the adjacent coast to the south of it. Almost every trace of the station has now been obliterated by the waves, but from plans which have been preserved it appears that its plan was that of an oblong with towers or bastions at each angle.[6] 3. OTHONA Or Ithanchester, near Bradwell-on-Sea, in Essex, was another important member of the Roman coast defences of Britain. It commanded the entrances of the Rivers Blackwater and Colne. Little now remains of Othona, although it is on record that the fortress enclosed an area of 4 acres, and that its walls possessed foundations no less than 14 feet in thickness. The defence of such a point as this against the incursions of foes was a matter of much importance, because this was a point on the coast of Britain specially susceptible to attack by marauders, and, as we shall see, special precautions were taken against attacks of this kind. [Illustration: FIG. 3. PLAN OF ROMAN BUILDING, WEST MERSEA, ESSEX]