Definify.com
Webster 1913 Edition
Shale
1.
A shell or husk; a cod or pod.
“The green shales of a bean.” Chapman.
2.
[G.
shale
.] (Geol.)
A fine-grained sedimentary rock of a thin, laminated, and often friable, structure.
Bituminous shale
. See under
Bituminous
.Shale
,Verb.
T.
To take off the shell or coat of; to shell.
Life, in its upper grades, was bursting its shell, or was
shaling
off its husk. I. Taylor.
Webster 1828 Edition
Shale
SHALE
,Verb.
T.
SHALE
,Noun.
1. A shell or husk.
2. In natural history, a species of shist or shistous clay; slate clay; generall of a bluish or yellowish gray color, more rarely of a dark blackish or reddish gray, or grayish black, or greenish color. Its fracture is slaty, and in water it molders into powder. It is often found in strata in coal mines, and commonly bears vegetable impressions. It is generally the forerunner of coal.
Bituminous shale is is a subvariety of argillaceous slate, is impregnated with bitumen, and burns with flame.