The surface may or may not be coated with some bituminous material.

Like all bituminous earths, it needs the strongest drying oil.

Bituminous may be distinguished from subbituminous by the manner of weathering.

There are gradations from bituminous coal into anthracite coal.

This hypothesis is based on experimental work with bituminous shales.

In that isle there are the bituminous springs which Herodotus has commemorated.

She mines one quarter of the bituminous coal of the United States.

The coal is of two varieties: bituminous and semi-bituminous.

It exists in large masses in the bituminous schists of Idria.

Produced during the distillation of bituminous coal for gas.