Columbia subject headings:
Mud.
Mudstone.
Sedimentary rocks.
Sediments (Geology)
Harvard subject headings:
Geology
Mud
Mudstone.
Paleontology
Sedimentary rocks
Sedimentary rocks.
Sedimentology
Sediments (Geology)
Princeton subject headings:
Mud.
Mudstone.
Sedimentary rocks.
Sediments (Geology)