Jurassic Dinoflagellate Research Articles

English Jurassic dinoflagellate cysts and acritarchs: A reexamination of some type and figured specimens

Abstract As a consequence of advances in knowledge of the morphology and relationships of dinoflagellate cysts and acritarchs and increasing sophistication in optical equipment, earlier descriptions of dinoflagellate cysts and acritarchs are in general obsolete; re‐descriptions are necessary to furnish fuller morphological information. In this paper are given the results of a reexamination of holotypes or figured specimens of 26 species of dinoflagellate cysts and 3 species of acritarchs, all from the Middle to Upper Jurassic (lower Callovian to Kimmeridgian) of England. The new species Gonyaulacysta setcheyensis and the new combination Acanthaulax downiei (Sarjeant) are proposed; two species, Heslertonia teichophera (Sarjeant) and Meiourogonyaulax? acanthosphaera (Sarjeant), are generically reassigned and emended; and the diagnosis of Leptodinium mosaicum (Downie) is emended. It is demonstrated that the genera Netrely‐tron Sarjeant and Paranett‐elytron Sarjeant do indeed possess an endoblast and are thus...

English Jurassic Dinoflagellate Cysts and Acritarchs: A Reexamination of Some Type and Figured Specimens

English Jurassic Dinoflagellate Cysts and Acritarchs: A Reexamination of Some Type and Figured Specimens

Early Tertiary ages from the coastal belt of the Franciscan complex, northern California

Dinoflagellates and angiosperm pollen from the Coastal belt of the Franciscan complex and Yager Formation in northern California establish an early Tertiary age no older than Eocene for numerous localities between Cape Mendocino and Fort Bragg. Until recently, the Coastal belt of the Franciscan complex has been mapped as Cretaceous. Several species of Wetzeliella Eisenack, a distinctive dinoflagellate genus that ranges in age from Paleocene to Miocene but is characteristic of Eocene strata, are especially conspicuous in samples from many of these localities. A few samples from the same area have yielded assemblages of Cretaceous palynomorphs. Evidence of redeposition of a Jurassic dinoflagellate species into Lower Cretaceous, lower Tertiary, and Eocene sediments and of Cretaceous dinoflagellates into lower Tertiary sediments appears in several samples.