The crushing, overthrusting and faulting that has affected the rocks of this system render it doubtful whether the coal seams which occur in it, even if of requisite thickness, can be worked to advantage. Some of the samples of coal obtained at the openings made near Yakutat bay were slickensided, showing that movements in the coal seam had there taken place. As already stated, the rocks of the Yakutat series are remarkably uniform in character throughout the extent now known, and offer but little variety. The sandstones are intersected in every direction by thin quartz seams, which stand in relief on the weathered surfaces, giving the rocks a peculiar and {170} characteristic appearance. The first important change in the geology along the route traversed by us was met on reaching Pinnacle pass. PINNACLE SYSTEM. The rocks of this system, as already stated, are best exposed in the great fault-scarp forming the northern wall of Pinnacle pass. They are more varied in composition and have preserved a better record of the conditions under which they were deposited than the sandstones and shales of the Yakutat system. Only an approximate section of the rocks exposed in the Pinnacle-pass cliff was obtained. Sandstone and conglomerate weathering into spires . . . 500 feet. Evenly bedded, sandy shale in thin layers . . . . . . . 600 " Coarse conglomerate; bowlders of crystalline rock . . . 50 " Thinly bedded, dark-colored sandstone and shale . . . . 500 " Reddish conglomerate . . . . . . . . . . . . . . . . . 10 " Light-gray sandstone, with thin, irregular coal seams . 40 " ----- Total . . . . . . . . . . . . . . . . . . . . . . . . 1,800 "