176

BOUNDARIES OF THE

UNITED STATES AND THE SEVERAL STATES

inaccessible as Everest is difficult to obtain, Corrections must be made to the observed altitude for refraction of the atmosphere, the shape of the geoid, and the varying amount of snow on the peak. For discussions of the height of Mount Everest, see De Graaff-Hunter (1955) and Gulatee (1954). (See fig. 54.)

The greatest ocean depth thus far discovered is in the Mariana Trench in the Pacific, about 200 miles southwest of Guam (lat 11°21' N., long 142°12′ E.). It has been called the Challenger Deep. The depth, measured by soundings in 1957, is 6,033+ fathoms, or 36,201 feet, and this value is generally accepted by scientific organizations. In 1960 the bathyscaph "Trieste" descended to the ocean floor in the same locality. It registered a depth of 5,967 fathoms-35,802 feet. (For a description of this descent, see Piccard, 1960, p. 224.) The greatest confirmed depth recorded in the Atlantic is 4,729 fathoms (28,374 feet). The position of this depth is in the Puerto Rico Trench, about 60

miles north of the eastern end of the Dominican Republic, at lat 19°35′ N., long 68°17′ W. This measurefrom the U.S.S. Archerfish in 1961.

The table below (table 10) lists extreme points in the cardinal directions, considering first the 50 States, then the continental United States, and finally the conterminous 48 States.

The southernmost point in U.S. territory is Rose Island of the Samoan group-almost exactly 1,000 miles south of the Equator. Point Barrow, the extreme north point of Alaska, is nearly 5,000 miles north of the Equator. (See fig. 10.)

Alaska with its islands extends from 130° W., past the 180° line to 17212° E., or 571° of longitude. The difference in time (3 hr, 50 min) between these two extremes is greater than that between New York and San Francisco.

The following distances in statute miles are computed to mean sea level: (a) West Quoddy Head, Maine, along the parallel to the Pacific Ocean, 2,807 miles; (b) the south point of Texas due north to the 49th parallel, 1,598 miles; (c) West Quoddy Head, Maine, to Cape Wrangell, Alaska, 4,839 miles; (d) West Quoddy Head, Maine, to Kure Island, Hawaii, 5,788 miles; (e) Mangrove Point, Fla., to Cape Wrangell, Alaska, 5,496 miles; (f) Mangrove Point, Fla., to Kure Island, Hawaii, 5,848 miles. The length of the northern boundary, excluding Alaska, is 3,987 miles; the Canadian-Alaskan boundary, 1,538 miles; and the Mexican

The two points farthest apart in the conterminous 48 States are West Quoddy Head, Maine, and Point Arena, California. The distance between them is 2,897 miles. From a point 10 miles south of Brunswick, Ga., to a point 12 miles south of San Diego, the distance is 2,088 miles, which is the shortest distance between two points, one on the Atlantic and one on the Pacific.

The highest point in North America is Mount McKinley, in Alaska, 20,320 feet above sea level (frontispiece).

The highest point within the conterminous 48 States is Mount Whitney-14,495 feet above sea level. The lowest point of dry land is in Death Valley-282 feet below sea level. These two points, both in California, are only 86 miles apart. (See figs. 50, 51.)