Giant Bathysiphon (Foraminiferida) from Cretaceous turbidites, northern California

Straight-sided, tubular fossils occur together with a diverse assemblage of deep-water trace fossils in linegrained Franciscan turbidites at Point Saint George. Pacific Coast of California. Based on comparison with living abyssal organisms and on skeletal microstructure, these tubes are interpreted as recrystallized siliceous tests of the large abyssohenthic foraminiferid, Bathysiphon. Tubes found preserved in-place show that life orientation of the Franciscan species was vertical with the broader, mature end protruding several millimetres above the muddy seafloor. Positioned in this way the organisms probably were suspension feeders or carnivores. Bathysiphon and trace fossils taken together reflect a diverse deep-water benthic community that was disrupted (or locally eliminated) repeatedly by turbidity currents reaching the outer margins of a submarine fan. ▭ Bathysiphon, deep-water benthos, outer fan/basin floor, trace fossils, Franciscan Complex, flysch, Cretaceous.