Nothing was done of any importance in this department during the second Spanish supremacy, but as soon as the country became a portion of the United States, the energy both of private individuals and the government rapidly increased the fund of geographical knowledge respecting it. The first map published was that of Vignoles, who, an engineer himself, and deriving his facts from a personal survey of the whole eastern coast from St. Marys river to Cape Florida, makes a very visible improvement on his predecessors. The canal contemplated at this period from the St. Johns or St. Marys to the Gulf gave occasion to levellings across the peninsula at two points, valuable for the hypsometrical data they furnish. Annexed to the report (February, 1829,) is a “Map of the Territory of Florida from its northern boundary to lat. 27° 30´ N. connected with the delta of the Mississippi,” giving the features of the country and separate plans of the harbors and bays. The same year J. R. Searcy issued a map of the territory, “constructed principally from authentic documents in the land office at Tallahassie,” favorably mentioned at the time.[128] The map prefixed to his View of West Florida, and subsequently to his later work, by Colonel Williams, largely based on his own researches, is a good exposition of all certainly known at that period about the geography of the country. Cape Romans is here first distinguished as an island; Sharks river is omitted; and Lake Myaco or Okee-chobee is not down, “simply,” says the author, “because I can find no reason for believing its existence!” Unparalleled as such an entire ignorance of a body of water with a superficies of twelve hundred square miles, in the midst of a State settled nigh half a century before any other in our Union, which had been governed for years by English, by Spanish, and by Americans, may be, it well illustrates the impassable character of those vast swamps and dense cypresses known as the Everglades; an impenetrability so complete as almost to justify the assertion of the State engineer, made as late as 1855: “These lands are now, and will continue to be, nearly as much unknown as the interior of Africa or the mountain sources of the Amazon.”[129] What little we know of this Terra Incognita, is derived from the notes of officers in the Indian wars, and the maps drawn up for the use of the army. Among these, that issued by the War Department at the request of General Taylor, in 1837, embracing the whole peninsula, that prefixed to Sprague’s History, which gives the northern portion with much minuteness, and the later one, in 1856, of the portion south of Tampa Bay, are the most important. The latter gives the topography of the Everglades and Big Cypress as far as ascertained.