gray, moderately to very fissile marine shale.
to cut thick pieces. Tends to part along
once a hammer makes hearty contact.
is the classic Mariposa, California
zone margin shale that has been uplifted
the Sierra foothills.
LIMEY SHALE, S-80A. California.
Somewhat fissile, pink to purplish gray-brown.
Effervesces and partly dissolves in acid. Check.
SHALE, S-80B. Colorado. Kerogen
or petroleum bearing "Green River Shale".
Also referred to as dolomitic marlstone.
SILTSTONE, S-85. California.
Light purplish gray. Lacustrine.
SILTSTONE, S-85A. California.
Light brownish, grayish or
brown to pinkish-red and a rose-purple color.
wide range of colors and again lacustrine.
LIMEY SILTSTONE, S-85B.
California. Pinkish gray. Some effervescence
SINTER (CALCAREOUS), see under TUFA
TRAVERTINE, S-90. California and various.
Calcium carbonate deposited often at the mouth of a hot spring
or in a limestone cave. Various colors from white
to tan, brown, yellows and reds in alternating bands and layers.
The larger the piece the better the layering and banding are displayed.
TUFA, see under LIMESTONE