Page:Popular Science Monthly Volume 53.djvu/600

580 corresponds in position to an extension of the basin of the Gulf of Mexico, toward which, from the Pacific side, there is a similar indentation of the continental mass as shown on map, Fig. 2. The Honduras basin, indenting the Central American plateau, has a corresponding depression across it at an altitude of about twenty-seven hundred feet. The Caribbean Sea proper has a more uniform



breadth than the other basins, and in like manner the American barrier, which is here narrower than farther north, is dissected in several places, as might be supposed. These depressions make it appear that the Caribbean basin was connected by several channels across the continent with the Pacific Ocean. The Nicaragua depression is the most northern. The elevation of the valley east of Lake Nicaragua is about three hundred and fifty feet above the sea, although the San Juan has further dissected it so as to reduce its