Fossiliferous

Fossiliferous is an adjective used in geology and paleontology to describe rocks or sediment layers that contain fossils or yield fossils upon examination. The term combines fossil- (from Latin fossilis, meaning dug up) with the suffix -iferous, meaning bearing or carrying. In practice, a fossiliferous interval may host macrofossils such as shells, bones, or teeth, as well as microfossils like foraminifera, ostracods, or pollen.

Fossiliferous rocks are primarily sedimentary, including limestone, shale, sandstone, chalk, and coal seams. The abundance and preservation of fossils depend on taphonomic conditions, diagenesis, and the depositional environment. Some deposits are rich and fossiliferous, yielding abundant specimens, while others are sparsely fossiliferous or nearly barren.

Fossiliferous strata are central to biostratigraphy and relative dating, as particular fossils serve as index fossils for correlating strata across regions. The quality of fossil preservation influences interpretive value; exceptional preservation can reveal details such as soft-tissue impressions, whereas poor preservation may limit identification.

Notable fossiliferous formations span geological time from the Paleozoic to more recent periods and contribute to understanding past biodiversity and paleoecology. The term is used descriptively in field notes, geological maps, and scientific reports to indicate the presence of fossils in a sample or sequence.