Jurassic radiolarians from chert and clastic rocks of the Chichibu Belt in the Toyohashi district, Aichi Prefecture, Southwest Japan.

Jurassic radiolarians were detected from 19 samples of chert, 12 samples of siliceous mudstone and 26 samples of mudstone of the Chichibu Belt in Toyohashi district, Aichi Prefecture, Southwest Japan. 69 species belonging to 39 genera are identified, and are shown in plates with undescribed morphotypes as a database for further study. Based on Jurassic radiolarian biostratigraphy presented by Hori (1990) and Matsuoka (1995a), the geologic ages of the examined chert, siliceous mudstone and mudstone samples range from early Early Jurassic to middle Middle Jurassic, middle Early Jurassic to late Middle Jurassic and middle Early Jurassic to early Late Jurassic, respectively.