The present remnants of the Heart Mountain thrust sheet are in an area about 36 miles north and south and about 24 miles east and west. The town of Cody, Wyoming, is located at about the middle of the eastern edge of the area. The largest remnant of the thrust is Sheep Mountain, and, although a detailed study of this remnant failed to disclose proof of the mechanics of thrusting or of the direction of movement of the thrust mass, it did uncover evidence indicating that the movement of the mass was to the northeast and that two small remnants near Sheep Mountain were placed in their present position as individual blocks, separated from the main mass of Sheep Mountain. The position of some previously unknown remnants of the thrust is described. Mechanics of thrusting are suggested that will permit the independent emplacement of the two rotated blocks near Sheep Mountain and also explain the great extent of the fault in the direction of its movement. A history of the region is given in outline form to indicate the age of the various earth movements.