Superposition, law of—in an undisturbed sequence of rocks younger beds
overlie older beds.
Syncline—a trough-like fold in the rocks, with the beds dipping inward
on either side. _See_ Anticline.
Talus—a mass of rock debris commonly on slopes or at the base of a steep
mountain or cliff.
Topography—the configuration of a land surface.
Unconformity—a break in the sequence of rock formations which separates
younger strata from older ones; caused primarily by removal of older
rocks by erosion before those of a later sequence were laid down.
Weathering—any natural process, mechanical or chemical, whereby rocks
are disintegrated or decomposed into smaller particles and
ultimately into clay and soil.