STANDING TALL: PLAINS INDIANS ENJOYED HEIGHT, HEALTH ADVANTAGE. COLUMBUS, Ohio - Equestrian Indian tribes on the American Plains in the late 1800s were the tallest people in the world, suggesting that they were surprisingly well-nourished given disease and their lifestyle, a new study found.
Limestone often contains variable amounts of silica in the form of chert (chalcedony, flint, jasper, etc.) or siliceous skeletal fragment (sponge spicules, diatoms, radiolarians), and varying amounts of clay, silt and sand (terrestrial detritus) carried in by rivers.
More than 50 percent of the surface rocks in Kentucky are limestones. Limestone is chiefly composed of the mineral calcite (calcium carbonate), but may contain small amounts of clay, silt, chert, and dolomite. Most limestones are layered and contain fossils of shellfish and other animals that lived in shallow seas.Limestones are shades of bluish gray to tan.ore than 50 percent of the surface rocks in Kentucky are limestones. Limestone is chiefly composed of the mineral calcite (calcium carbonate), but may contain small amounts of clay, silt, chert, and dolomite. Most limestones are layered and contain fossils of shellfish and other animals that lived in shallow seas.