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). 85-87. Hystrichosphaeridium truswelliae (Sample 189-1172D-20R-5, 40-43 cm) (1). 88, 89. Hystrichosphaeridium tubiferum (Sample 189-1172D-20-5, 40-43 cm) (1). 90, 91. Hystrichosphaeropsis sp. (Sample 189-1172D-16R-2, 40-42 cm) (1). 92, 93. Impagidinium cassiculum (Sample 189-1172D-14R-1, 40-42 cm) (1). 94, 95. Impagidinium dispertitum (Sample 189-1172D-8R-6, 40-42 cm) (1). 96. Impagidinium maculatum (Sample 189-1172D-14R-1, 40-42 cm) (1).