On July 8-19, 1539, according to the collection of Ramusio, three vessels sent out by Cortés to discover unknown lands—“Of Which Fleete was Captaine the right worshipfull knight Francis de Vlloa borne in the Citie of Merida”—sailed from Acapulco.[25] Skirting the mainland northwestward, they explored Mar de Cortés, or Gulf of California; and on September 24 (as fixed by interpolation from Ulloa’s excellent itinerary) they descried and described the features of the coast in such fashion as to locate their vessels (one was already lost) off the southern point of Tiburon, and in sight of the islands of San Esteban and San Lorenzo, as well as locally prominent points on the mainland of Lower California. Here they “discerned the countrey to be plaine, and certaine mountaines, and it seemed that a certaine gut of water like a brooke ran through the plaine” (p. 322). Judging from other geographic details, this “gut of water” was certainly the tide-torn gateway now named Boca Infierno; while the next day’s sailing (it is noteworthy that this was “north” instead of northwestward as usual) carried them by “a circuit or bay of 6 leagues into the land with many coones or creeks”, evidently Bahia Tepopa with the northern end of the turbulent strait El Infiernillo. The record shows clearly that Ulloa discovered Tiburon, but failed (quite naturally, in view of the route pursued and the peculiar configuration at both extremities of the strait) to perceive its insular character. No mention is made of inhabitants or habitations on this land-mass, though both are described on the neighboring island of Angel de la Guarda in terms that would be applicable to the Seri. [25] The Voyages of the English Nation to America, collected by Richard Hakluyt and edited by Edmund Goldsmid, 1890, vol. III, p. 317.