a number of small cays of Æolian formation, which, originally detached, have now been joined together by ridges of sand. This formation is still going on to the southward, and an outer line, similar to the Palisades, is gradually being built up on the numerous small detached cays which lie between East and South-east Cays.

When the Spaniards discovered Jamaica the present Palisades were in much the same condition as the outer line is now-that is to say, there was a line of detached cays, connected by banks of loose, shifting sand, which were submerged at high water, with here and there channels of sufficient depth to admit of the passage of small vessels. In 1635, when Colonel Jackson, the English adventurer, attacked and plundered St. Jago de la Vega, the capital of Jamaica, the small cay of calcareous rock, which ultimately became the nucleus of Port Royal, was separated from the Palisades by a channel sufficiently deep for his ships to pass through. Twenty years later when Venables captured the island from the Spaniards, this channel was closed by a narrow bank of sand barely rising above the water, and those who had accompanied the former expedition remarked upon the change which had taken place From that date the sand seems to have accumulated rapidly, and before long the Palisades became one continuous tongue of sand, extending from the mainland of the island on the east to Port Royal Point on the west.

The Spaniards, during the century and a half that they held Jamaica, never erected any buildings upon Cagua, or Punto de Caguaya, as the cay at the western extremity of the Palisades was termed by them.^[1] Indeed, in their day the site was not at all suitable, for during the prevalence of strong breezes the sand was swept hither and thither by the sea, and a great portion of the cay submerged. After, however, the cay had become joined to the Palisades, and the sand ridge had risen two or three feet above high water, Cagua, or Careening Point, as the English called it, became a good position from which to defend the entrance of the harbor. The first work, which mounted twenty-one small guns, but consisted merely of a stockade with a wall of