| Silicon is used as a structural material in the diatom shell, the radiolarian and heliozoan spicule, and the chrysophyte exoskeleton. |
| The sequence includes tuffaceous sandstone, andesitic sandstone and radiolarian chert. |
| Calcareous oozes are common in the low and mid-latitudes while in other places, particularly the high latitudes, radiolarian oozes tend to dominate. |
| Subsequently the massive sulfide deposit and surrounding metalliferous sediment apron were covered by oceanic radiolarian chert sediments. |
| They are found in the northern part of the AFERNOD zone and are associated with clayey radiolarian silts. |
| A larger number of new forms has been found in the radiolarian ooze collected by the Challenger, and others fossil in Barbados. |
