Plate P1. Illustrations of taxa, sample, and slide number. Scale bar = ~20 µm unless stated otherwise. Scanning electron microscope (SEM) photographs have varying scale bars. 1. Adnatosphaeridium multispinosum (Sample 189-1172D-15R-3, 40-42cm) (1). 2. Aio

Plate P1 (continued). 181. Histiocysta sp., (possibly Microdinium) (Sample 189-1172D-23R-1, 41-43 cm) (SEM). 182. Hystrichokolpoma spinosum (Sample 189-1172D-12R-7, 40-42 cm) (SEM). 183-185. Hystrichosphaeridium truswelliae (SEM); (183) Sample 189-1172D-3R-4, 40-42 cm (operculum); (184, 185) Sample 189-1172D-23R-1, 41-43 cm; (185: detail antapical processes). 186. Impagidinium cassiculum (Sample 189-1172D-12R-7, 40-42 cm) (SEM). 187. Impagidinium dispertitum (Sample 189-1172A-39X-4, 147-149 cm) (SEM). 188. Impagidinium spp. (Sample 189-1172D-3R-4, 40-42 cm) (SEM). 189. Manumiella druggii transition to Manumiella rotundata (Sample 189-1172D-29R-5, 40-42 cm) (SEM). 190-192. Operculodinum? sp. A (Sample 189-1172D-24R-5, 40-42 cm) (SEM).