Slab of clayey shell hash limestone

Polished slab of clayey shell hash limestone, showing fragmented plates
of calcareous algae and complete and broken shells of brachiopods,
pelecypods, and gastropods, with other indeterminate remains, embedded
in non-calcareous clay matrix. Most of the fossils are oriented more or less
parallel to bedding, but scattered pieces, often in small clumps, are oblique
to vertical. This kind of fabric is typical of skeletal material deposited rapidly
in a high-energy setting, most likely during storms. At the lower left is a
region of iron oxide cementation. When placed in water, clay matrix that
is free of iron oxide slakes away, freeing the fossils.

View close-up of slab
View shell hash limestone in water

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