A rock formed from deposits of shell fragment is Limestone.
A sedimentary rock that is sometimes formed by deposits of shell fragments is LIMESTONE!!
A clastic rock.
Coquina is a soft limestone that is formed from the cemented fossil debris of coarse shells and shell fragments. It is a non-foliated rock.
Limestone can be formed partly or mostly by visible shell fragments. .
clastic
sedimentary
Limestone. However most large masses of limestone formed from coral reefs, not shells. The shell fossils in this limestone are "incidentals" due to shell dwelling organisms living on the periphery of the reef, not the bulk of the limestone.
Sedimentary rock is the rock formed as a result of deposits from weathering and erosion. Sedimentary rock can be millions of years old.
A sedimentary rock formed from sand deposits is called a 'Sandstone' or generically a 'Psammite'.
A Clastic sedimentary rock forms when fragments of preexisting rocks are compacted or cemented together. A Bioclastic rock is a clastic rock but the fragments are not of preexisting rock but of organic shell and or bone fragments.
Sedimentary rock
clastic rock