Gaarderella granulifera Black, 1973
Placoliths comprise a cretarhabdid pelaga formed of non-imbricate segments enclosing a central area occupied by a granulated structure devoid of pores. The central area lacks both an axial cross and a distal process.
In plan view under crossed polars, the pelaga displays first-order, greyish-white interference colours; the shields are dimmer than the tube cycle and exhibit inclined extinction and length-fast (–) elongation. The central area shows whitish-grey interference colours and has a rough margin.
Black, M. 1973. British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph 127: 49-112.