Article: Radiolaria from the Namurian of Derbyshire
B. K. Holdsworth
Albaillella pennata sp. nov. and Popofskyellum undulatum Deflandre are described from calcareous concretions at the horizon of the goniatite Reticuloceras paucicrenulatum Bisat and Hudson. The diagnosis of the genus Albaillella is emended. It is suggested that A. pennata and P. undulatum may possibly have been favoured by depths of water greater than those necessary for the proliferation of Namurian spumelline Radiolaria, and that depths favouring these two forms may have been attained only rarely during the deposition of Namurian goniatite bands in Derbyshire and Staffordshire.