loess

to gather or collect.

layer of gases surrounding Earth.

to cover entirely.

chemical compound (CaCO3) found in most shells and many rocks.

steep wall of rock, earth, or ice.

type of mineral that is clear and, when viewed under a microscope, has a repeating pattern of atoms and molecules.

area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

tiny, dry particles of material solid enough for wind to carry.

to wear away.

very large.

able to produce crops or sustain agriculture.

very thin.

mass of ice that moves slowly over land.

type of plant with narrow leaves.

grassland region of North America, between the Rocky Mountains and the Mississippi River.

windblown soil or silt.

type of mineral that can be split into thin, see-through sheets.

inorganic material that has a characteristic chemical composition and specific crystal structure.

(4,382 kilometers/2,723 miles) river in the western United States.

wetness.

composed of living or once-living material.

nearly white or lacking in color.

small piece of material.

common type of mineral.

natural substance composed of solid mineral matter.

part of a plant that secures it in the soil, obtains water and nutrients, and often stores food made by leaves.

small, loose grains of disintegrated rocks.

solid material transported and deposited by water, ice, and wind.

small sediment particles.

bones of a body.

top layer of the Earth's surface where plants can grow.

body of flowing fluid.

rock, earth, and gravel left behind by a retreating or melting glacier.

movement of air (from a high pressure zone to a low pressure zone) caused by the uneven heating of the Earth by the sun.

(5,464 kilometers/3,395 miles) river in China. Also called the Huang River.