Laccolith
An igneous intrusion that forces apart two layers of strata and forms a mound-shaped body much wider than it is thick.

Lacustrine
A lake or pond ecosystem.

Lagomorph
Pikas, rabbits, and hares.

Landform
Any feature of the Earth's surface having a characteristic shape as the product of natural processes. Examples are continents, ocean basins, mountains, alluvial fans, sand dunes, and valleys.

Landslide
A general term covering the failure and rapid movement of rock masses downslope on the Earth's surface.

Larva
An insect, amphibian, or other pre-adult form of an animal that differs strongly from the adult form.

Lateral
Pertaining to the side.

Lava
A general term for a molten extrusive; also, for the rock that is solidified from it.

Lava Flow
Magma that flows out at the Earth's surface.

Lenticular
Lens-shaped.

Lichen
Any of a large number of small plants made up of an alga and a fungus growing symbiotically on various solid surfaces, such as rocks.

Life Zone
A zone defined by elevation and latitude that hosts a characteristic assemblage of plants.

Limestone
A sedimentary rock consisting chiefly of calcium carbonate, mainly in the form of the mineral calcite.

Linear
Long and narrow, such as a blade of grass.

Lithics
Tools made of stone, including arrowheads, spear points, metates, manos, and a range of chippers, scrapers, hammers, and stone knives and blades.

Lithology
A description of a rock, especially one base on the properties that can be seen in a hand specimen.

Llano
Spanish for "plain."

Luster
The surface appearance of a substance, or the manner in which it reflects light.