Dislocation at Thirtymile Point, New York
Observations On the shore of lake Ontario, 30 miles east of the mouth of the Niagara river, is a bluff point on which a lighthouse stands. The waves are there actively engaged in eating back the shore, and their work has produced a cliff about 20 feet high, exhibiting red shale of the Medina formation, with a thin cover of drift. The shale is of variable texture, some of its layers being so arenaceous as almost to deserve the name of sandstone. The strata lie nearly horizontal, except at one place. At the apex of the cape is a fractured anticline, and this is accompanied by a vertical dislocation of 6 feet, the uplift being on the northeast side. The axis of the disturbance trends northwest and southeast, and the outline of the coast is such that the disturbance reappears in the bluff about 200 feet to the eastward. There . . .