The Panama line comes most properly the first point for consideration. Here the survey, by Lieutenant Lloyd, in 1829, gives some certain data, and some curious and important information. He tells us (p. 091) pointedly, from actual observation, that which good Spanish maps indicated, and what was more vaguely told by others. According to him, on the eastern side of the province of Veragua, the Cordillera breaks into detached mountains, their sides exhibiting only bare rock, almost perpendicular. To these, as approaching nearer Panama, succeed numerous conical mountains, arising out of savannahs and plains, and seldom exceeding from 300 to 500 feet. "Finally," says he, "between Chagre on the Atlantic side, and Chorera on the Pacific, these conical mountains are not so numerous, having plains of great extent, interspersed with occasional ranges of hills of inconsiderable height." Such is the Isthmus of Panama, where the distance from sea to sea is, even according to the present charts, only 30 geographical miles, and from the mouth of the Chagre to Panama, 33 miles.[18] Of this distance the Chagre, which has a circuitous course, is navigable for 40 miles to Cruces--distant from the sea in a direct line 21 miles, and from Panama 14 miles. At its mouth the Chagre is one-fourth of a mile broad, and at Cruces about 150 feet: in its middle course the depth is 24 feet. The current runs at the rate of from three to four miles per hour. It is full of numerous, constantly shifting sand banks, and sunken trees, which, with the current, render the navigation (p. 092) tedious, difficult, and even dangerous. At its mouth the coast is very sickly, as indeed the country through its course also is; but when the land is cleared, it will doubtless become more healthy. When the current is very rapid, it requires four or five days to reach Cruces. The height of the land which intervenes between Cruces and Panama, has been accurately ascertained by Mr. Lloyd; and that portion of the country which he passed over in his survey along the old road to Panama, is certainly the most elevated of the whole, as is shown in the following summary of his survey.