The islands belonging to Spanish North America near its coasts, are numerous, both in the Atlantic and Pacific Oceans, but most of them are either uninhabited or unimportant from their being small. Commencing on the north-east shores of the Intendancy of San Luis Potosi, and proceeding along its maritime borders southward, we meet with very numerous long strips of insulated land, the very names of most of which are unknown; but from their situation, they must be very fertile and will probably soon become of some use; such are the islands in the bays of Galveston, St. Bernardo, at the estuary of the great Rio Bravo del Norte, and on the coast of New Santander; of these the island of _St. Luis_, which embraces the above-mentioned bays, is one of the largest, with the island of _St. Josef_, extending from the bay of St. Bernardo to Lake Espiritu Santo, and _La Carbonera_, reaching from the same lake to the Barra de Santander. On the coasts of the Intendancy of Vera Cruz are the island of _Ramirez_ in the gulf or lake of Tamiagua, a large isle in the centre, and the smaller island of _Tore_. In the bay of Vera Cruz are the islands of _Sacrifices_, _Juan de Ulua_, and others, which are small and sandy. _Juan de Ulua_ was first visited by Grijalva, in 1518, who gave it the name of Ulua, from having seen the remains of some human sacrifices, which the natives told him they were in the habit of offering here by order of the king of Acolhua. The interpreters who only spoke the language of Yucatan called the Mayo, believed that Acolhua or Ulua was the name of the island. A very strong fortress called the castle of St. Juan dʼUlua now covers nearly the whole rock, in the form of an irregular square, with advanced works towards the sea front; the expense of finishing this fortress is said to have been upwards of eight millions sterling; it contains fine barracks, cisterns, and a newly erected giratory light-house, placed at its eastern extremity, which was built according to the plan of M. Mendoza, the astronomer, who lately died in London. It consists of a high tower, on the top of which is the lantern with the lamps fixed on a triangle, turning by means of clock-work; the lights disappearing alternately, are supplied with a current of air and reflectors. This beautiful building cost about 20,000_l._ and is worthy of notice, on account of its utility in so dangerous a navigation as the channel of Vera Cruz is at all times. The island of _Sacrifices_ was so called, from the first discoverers observing the numerous remains of the victims immolated by the Mexican priests. In the environs of the river Alvarado, several rivers descending from the interior, form numerous islands at their junction with the sea, and farther to the south are the islands of _Guascualco_ at the mouth of the river of the same name and the island of _Tabasco_ on which that town is situated.