The castle of Bullock, standing immediately above the little harbour of the same name, not far from the Dalkey station of the Dublin, Wicklow, and Wexford Railway, is worth a visit. It has been very carefully restored, and is now used as a residence. The castle of Dalkey is used as a town hall. [Illustration: Bullock Castle, near Kingstown, Co. Dublin.] Of the origin of these very interesting structures, no notice, as far as we could ascertain, has been preserved. It is extremely probable that they were erected by English settlers, not long after the Anglo-Norman invasion of Ireland--their architectural features indicating an early period; and similar buildings, connected together by a wall enclosing a very considerable space, occur in several localities known to have been occupied by the early English. We may here also mention the picturesque and well-preserved castle of Drimnagh, lying at a distance of about four miles from Dublin, on the road to Crumlin. Its bawn is still perfect, and the ancient fosse, by which the whole was enclosed, remains in fine preservation, and is still deep. Drimnagh was considered a place of considerable strength during the rising of 1641, and it appears to have been strengthened, and in a great measure re-edified, about that unhappy period of Ireland’s history. In Swords are the dilapidated remains of what was once a fine mediæval castle and bawn, which belonged to the Archbishops of Dublin. There are the remains of other castles, small keeps, and castellated mansions in the neighbourhood of Dublin, particularly in the south, which lay open to the predatory incursions of the lawless tribes that once inhabited the Wicklow Mountains. CHAPTER XVII. TOWN GATES AND WALLS: BRIDGES. DROGHEDA GATES--‘SHEEP’ GATE, TRIM--WALLS OF ATHENRY--KILMALLOCK WALLS--WALLS OF LONDONDERRY--BRIDGES--KILLALOE BRIDGE--OLD THOMOND BRIDGE--NEWBRIDGE.