Leptinite, a fine-grained granitic rock.

Loam, a soil composed of siliceous sand, clay, carbonate of lime, oxide of iron, magnesia, and various salts, and also decayed vegetable and animal matter.

Loess, a term usually applied to a tertiary deposit on the banks of the Rhine.

Lumbar, the vertebræ near the loins.

Mammalia, that class of animals characterized by the female suckling its young.

Marl, a mixed earthy substance, consisting of carbonate of lime, clay, and siliceous sand.

Mastoid, a process situated at the posterior part of the temporal bone.

Matrix, a mould; the cavity in which a thing is held.

Maxillary, the upper jaw bone.