![File:Uintacrinus socialis fossil crinoids in chalk (Niobrara Formation, Upper Cretaceous; western Kansas, USA) 7 (15115688847).jpg - Wikimedia Commons File:Uintacrinus socialis fossil crinoids in chalk (Niobrara Formation, Upper Cretaceous; western Kansas, USA) 7 (15115688847).jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/0/02/Uintacrinus_socialis_fossil_crinoids_in_chalk_%28Niobrara_Formation%2C_Upper_Cretaceous%3B_western_Kansas%2C_USA%29_7_%2815115688847%29.jpg)
File:Uintacrinus socialis fossil crinoids in chalk (Niobrara Formation, Upper Cretaceous; western Kansas, USA) 7 (15115688847).jpg - Wikimedia Commons
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The English Chalk and London Clay: two remarkable British bony fish Lagerstätten | Geological Society, London, Special Publications
![File:Uintacrinus socialis fossil crinoids in chalk (Niobrara Formation, Upper Cretaceous; western Kansas, USA) 9 (15115469629).jpg - Wikimedia Commons File:Uintacrinus socialis fossil crinoids in chalk (Niobrara Formation, Upper Cretaceous; western Kansas, USA) 9 (15115469629).jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/e/ea/Uintacrinus_socialis_fossil_crinoids_in_chalk_%28Niobrara_Formation%2C_Upper_Cretaceous%3B_western_Kansas%2C_USA%29_9_%2815115469629%29.jpg)
File:Uintacrinus socialis fossil crinoids in chalk (Niobrara Formation, Upper Cretaceous; western Kansas, USA) 9 (15115469629).jpg - Wikimedia Commons
![Fossils For Sale | Fossils-UK.com | Rare British Cretaceous Chalk Fossil Fish from Lewes, Sussex, England:- Hoplopteryx lewesiensis Fossils For Sale | Fossils-UK.com | Rare British Cretaceous Chalk Fossil Fish from Lewes, Sussex, England:- Hoplopteryx lewesiensis](https://www.fossils-uk.com/images/rare-british-cretaceous-chalk-fossil-fish-from-lewes-sussex-england-sku-v2972-hoplopteryx-lewesiensis-p5833-16726_image.jpg)