Mississippi valley. Successive terraces that formed in lower Mississippi Valley during Pleistocene glaciations are shown in this highly schematic cross section. The terraces, with the oldest at the top, were flood plains laid down between glaciations. During each glacial period the river rejuvenated by the consequent fall in sea level and the consequent drop in its mouth, cut deeply into the preceding floodplain. The Prairie terrace represents between the early Wisconsin and late Wisconsin glaciation. Haag, 1962.

Mississippi valley. Slope of terraces is illustrated in this schematic longtitudinal section of lower Mississippi and Gulf region. The weight of the accummulated sediments at the bottom, made with the oldest deposits at the bottom, made the crustal rock sink and the adjacent land rise like a great lever with the fulcrum near the coast. Because of this tilt, the floodplains laid down during interglacial periods remained as terraces. The broken horizontal line marks present sea level. Hatched area is the older material of the continental crust. Haag, 1962.

Mississippi valley. Effects of glacial advance and retreat on rivers entering Gulf of Mexico are shown in these diagrams. Upper block of each pair is river valley, lower block is mouth of the river. At left glaciers have lowered sea level. River flows faster and cuts deep, straight valley. At right, glaciers melt, mouth of river rises and river deposits sediments to make flood plain in valley and delta at mouth. Haag, 1962.

Mississippi valley. Effects of glacial advance and retreat on rivers entering Gulf of Mexico are shown in these diagrams. Upper block of each pair is river valley, lower block is mouth of river. At left, crust under Gulf sinks, raising the river valley. At right cycle is repeated at next glaciation and intergalcial. Haag, 1962.

Mississippian tectonic map (Raasch et al., 1961, v. 1, p. 447).

Missouri Coteau, extension of Altamont (Mankato?) moraine in North Dakota. Lacustrine sediments in the foreground, south of Elrose, Sask.

Missouri River looking west, upstream. Near bridge crossing Missouri River along Malta-Lewistown highway, Montana, May, 1964.

Missouri River near Wolf Point, Montana. Fort Union (Paleocene) highland in background. Identity of individuals in photograph unknown.

View from the Peruvian Gulf Oil Co's office window towards modern office on Avenida Abancay, Lima.

Mokka Fiord Dome. Axel Heiberg Island. Airphoto A 16858-33.

Monument to David Thompson, near Velva, N.D., made of granite. May, 1962.

The moon is seen rising over a lake near La Ronge, Saskatchewan.

Moose Mountain Creek - meltwater channel at sunset.

Moraine dammed lake near Macusani.

Moraine. Knob and kettle topography. Southeast of Eastend along highway 13.