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Having the qualities of chalk;abounding with chalk; chalky; as, cretaceous rocks and formations. See Chalk. Cretaceous acid, an old name for carbonic acid. -- Cretaceous formation (Geol.), the series of strata of various kinds, including beds of chalk, green sand, etc., formed in the Cretaceous period; -- called also…

Of, pertaining to, or designating, the period of time following the Jurassic and preceding the Eocene.

In a chalky manner; as chalk.

Same as Supracretaceous.

Lying above the chalk; Supercretaceous.

A cephalopod of the extinct genus Baculites, found fossil in the Cretaceous rocks. It is like an uncoiled ammonite.

and belonging to an extinct family. The belemnites are found in rocks of the Jurassic and Cretaceous ages. -- Bel*em*nit"ic, a.

lk drawing (Fine Arts), a drawing made with crayons. See Crayon. -- Chalk formation. See Cretaceous formation, under Cretaceous. -- Chalk line, a cord rubbed with chalk, used for making straight lines on boards or other material, as a guide in cutting or in arranging work. -- Chalk mixture, a preparation of chalk, c…

A subdivision of the cretaceous formation of western North America, especially developed in Colorado and the upper Missouri region.

Chalky; cretaceous. [Obs.] Ash.

A subdivision at the base of the cretaceous formation in Western North America; -- so named from the region where the strata were first studied.

An extinct, long-necked, marine, cretaceous reptile from Kansas, allied to Plesiosaurus.

A genus of extinct Cretaceous fishes; -- so named from their spear-shaped teeth. They were allied to the pike (Esox).

A genus of Cretaceous fossil shells allied to oysters.

A cretaceous fossil sea urchin of the genus Galerites.

ds of clay and marl in the South of England, between the upper and lower greensand of the Cretaceous period.

A genus of cretaceous fossil shells allied to the oyster.

American herbivorous dinosaur of great size, allied to the iguanodon. It is found in the Cretaceous formation.

A genus of large, extinct, wingless birds from the Cretaceous deposits of Kansas, belonging to the Odontornithes. They had teeth, and were essentially carnivorous swimming ostriches. Several species are known. See Illust. in Append.

-shaped under valve, with a flattish upper valve or lid. Hippurites are found only in the Cretaceous rocks.