Pennsylvanian—the sixth [period] of the [Paleozoic] [Era] (see [p. 3]).
Period—a unit of geologic time, a subdivision of an [era].
Permian—the last [period] of the [Paleozoic] [Era] (see [p. 3]).
Physiographic outline map—shows location of natural regions ([p. 42]).
Playa lake—a temporary shallow lake in a nearly level, closed basin, which has no drainage outlet.
Pleistocene—the first [epoch] of the [Quaternary] [Period] (see [p. 3]).
Pliocene—the last [epoch] of the [Tertiary] [Period] (see [p. 3]).
Precambrian—comprises the Early and the Late [Precambrian] [Eras], the earliest great divisions of geologic time. Rocks that formed more than 600 million years ago are known as Precambrian rocks.
Pyritohedron—a solid that has twelve 5-sided faces.
Quaternary—the present [period] of geologic time; the second period of the [Cenozoic] [Era] (see [p. 3]).