Graham Eaton / Vertical beds of Cretaceous chalk, with layers of flint and rotated normal faults, Jurrasic Coast, near Durdle Door, Dorset, England, UK.

Will Watson / Natural limestone boulder from the Cretaceous Period located in a meadow with Spreading Bellfolower (Campula patula), Carpathian Biosphere Reserve, UNESCO World Heritage Site, Zakarpattia Oblast, Ukra...

John Cancalosi / Fossil stromatolite from Cretaceous age, 145-65 million years ago, Merzouga, Khenifra province, Morocco

John Cancalosi / Fossil ammonite (Surriceras sp) from Cretaceous period, Morocco

John Cancalosi / Ammonite (Cleoniceras besairei) Lower Cretaceous, Mahajanga, Madagascar

Paul D Stewart / Ammonite (Placenticeras) shell from upper Cretaceous period 75 million year ago, showing iridescent ammolite gem skin, cracked and flaked in the typical 'dragon skin' pattern.

Will Watson / Flint nodule or Adder / Hag stone, with central hole, formed in the upper Cretaceous Period circa 80 million years old, Hertfordshire, England, UK.

John Cancalosi / Mookaite, a brecciated radiolarite, composed of fossil radiolarians, Western Australia, Cretaceous period.

Kevin Schafer / Badlands with sediments from the Cretaceous, Drumheller, Alberta, Canada

Adrian Davies / Fossil Mayfly, specimen approx 15mm long. Lower Cretaceous period from Crato Formation, Nova Olinda Member, Ceara, Brazil

Juan Carlos Munoz / Fossil of shrimp-like crustacean (Antrimpos) from the Cretaceous period, Germany

Juan Carlos Munoz / Fossil of Oak leaf (Quercus pseudocasta) angiosperm from the Cretaceous period