Ellipsagelosphaera britannica

Coccolithus britannicus Stradner, 1963

The elliptical placolith consists of single-tiered distal and proximal shields, a double tube cycle and a central area spanned by a disjunct traverse bar. All parts except the outer tube cycle exhibit inclined extinction lines and length-fast (-) elongation. The outer tube cycle exhibits constant extinction because the optic is vertical relative to the microscope stage in the plan view. The extinction lines are dextrogyre on the distal side, and their typical angle is about 67° on the distal shield, but they can not be measured in the tube cycle due to the oblique orientation of the tube cycle segments. The apparent angle between extinction on the tube cycle is 73°, corresponding to an
obliquity angle of 17°.

Perch-Nielsen, K., 1968c. Der Feinbau und die Klassifikation der Coccolithen aus dem Maastrichtien von Danemark. Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab 16, 1-96.

Stradner, H. 1963. New contributions to Mesozoic stratigraphy by means of nannofossils. Proceedings of the Sixth World Petroleum Congress. Section 1 Paper 4: 167-183.