Helicosphaera californiana Bukry, 1981b
Helicolith has a Type I (Helicosphaeroides ampliaperta type) blanket, an expanded flange termination and a central area with a narrow elongated central opening without any structure.
Helicosphaeroides californiana differs from Helicosphaeroides mullerae (Varol, 1989) Varol, n. comb. by lacking an oblique bar therefore it is possible to confuse with the latter when the bar is removed by adverse environmental conditions.
Bukry, D., 1981b. Pacific coast coccolith stratigraphy between Point Conception and Cabo Orientes, Deep Sea Drilling Project Leg 63. Initial Reports of the Deep Sea Drilling Project 63, 445-471.
Varol, O., 1989a. Calcareous nannofossil study of the central and western Solomon Islands. Vedder, J.G., Bruns, T.R., (eds.), Geology and offshore resources of Pacific island arc-Solomon Island and Bougainville, Papua New Guinea Regions: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources Earth Sciences Series vol. 12, pp. 239-268.
USGS dart core GSCD-125, California Continental Borderland, USA