The mountains on the northern border of the seaward-stretching table-lands, both southeast and northwest of Yakutat bay, are abrupt and present steep southward-facing bluffs. This escarpment is formed of stratified sandstones and shales, and owes its origin to the upheaval of the rocks along a line of fracture. In other words, it is a gigantic fault scarp. The gravel and bowlders forming the plateau extending oceanward have been accumulating on a depressed orographic block (or mass of strata moved as a unit by mountain-making forces), which has undergone some movement in very recent times, as is recorded by a terrace on the fault scarp bordering it. West of Yakutat the geological structure is more complex, and long mountain spurs project into the platform of ice skirting the ocean. Filling the valleys between the mountain spurs, there are many large seaward-flowing glaciers, tributary to the great Piedmont ice-sheet. * * * * * This brief sketch of the geography of Yakutat bay, together with the accompanying outline map of Alaska (plate 2), will, it is hoped, aid in making intelligible the following historical sketch and the narrative of the present expedition. [Illustration: PLATE 2. SKETCH MAP OF ALASKA.] {58} PART I. PREVIOUS EXPLORATIONS IN THE ST. ELIAS REGION.[2] [Footnote 2: For more complete bibliographic references than space will allow in this paper, the reader is referred to Dall and Baker's "Partial list of books, pamphlets, papers in serials, journals and other publications on Alaska and adjacent regions;" in Pacific Coast Pilot: Coasts and Inlets of Alaska; second series. U. S. Coast and Geodetic Survey, Washington, 1879; 4°, pp. 225-375.] BERING, 1741. The first discovery of the southern coast of Alaska was made by Vitus Bering and Alexei Cherikof, in the vessels _St. Peter_ and _St. Paul_, in 1741. On July 20 of that year, Bering saw the mountains of the mainland, but anchored his vessels at Kyak island, 180 miles west of Yakutat bay, without touching the continental shore. A towering, snow-clad summit northeast of Kyak island was named "Mount St. Elias," after the patron saint of the day. COOK, 1778. The next explorer to visit this portion of Alaska was Captain James Cook, who sailed past the entrance of Yakutat bay on May 4, 1778. Thinking that this was the bay in which Bering anchored, he named it "Bering's bay." Mount St. Elias was seen in the northwest at a distance of 40 leagues, but no attempt was made to measure its height. LA PÉROUSE, 1786.[3] [Footnote 3: Voyage de la Pérouse autour du monde. Four vols., 4°, and atlas; Paris, 1797; vol. 2, pp. 130-150.] Yakutat bay, in which we are specially interested, was next seen by the celebrated French navigator, J. F. G. de la Pérouse, in command of the frigates _La Boussole_ and _L'Astrolabe_, on June 23, 1786.