(Riedel and Sanfilippo, 1970)
The top of the zone is defined by the earliest evolutionary appearance of Stichocorys peregrina and is coincident with the lower limit of the Stichocorys peregrina Zone.
The base of the zone is defined by the earliest evolutionary appearance of Didymocyrtis penultima and is coincident with the upper limit of the Didymocyrtis antepenultima Zone.
Although equivalent to the low-latitude zone of the same name, the aspect of the fauna in middle latitudes is often different and important marker species are frequently missing.
Reference slides R 56.1, R 56.2 and R 56.3 from Sample 32-310-8-5, 136-146 cm.