“…These beds yield an admixture of faunal assemblages of foraminifers, including larger benthic foraminifers (mainly Nummulites), smaller benthic foraminifers (Quinqueloculina sp., Triloculina sp., Cibicides sp., Turrilina sp., and Lagena sp.) [17] [18] was the first to study in detail the microfaunal assemblages of the area. On the basis of stratigraphic ranges of planktonic foraminiferal species, [19] identified five biozones of middle to late Eocene age from the Kopili Formation of Mikir-North Cachar Hills, Assam: Truncorotaloides topilensis Zone, Truncorotaloides rohri Zone, Globigerapsissemi involuta Zone, Cribrohantkenina inflata Zone, Globigerina gortanii Zone.…”