Well-worn pebbles of amorphous quartz (agate, chalcedony, jasper, &c.) are found in the stratified drift along the western side of the Tertiary region of the state, and from Columbus northward.
The stratified rocks of the Great Plains, the Parks, and the Plateaus contain enormous quantities of coal.
The survey uses a complex stratified sample, the theory of which was not touched on in his degree.
The well stratified layers are being removed in chronological sequence.
The till is presumably made in part of preglacial soils, but it is more largely composed of rock waste mechanically comminuted by the crccpiiig ice sheets; although the crystalline rocks from Canada and some of the more resistant stratified rocks south of the Great Lakes occur as boulders and stones, a great part of the till has been crushed and ground to a clayey texture.
