Foraminifera from the Nodular Limestone, Bilthana, Gujarat: Stratigraphic Significance

On the basis of field and microfaunal evidences the Nodular Limestone of Bilthana and Man River Sections are considered to be the same lithounit, though different stratigraphic nomenclatures have been used for these two regions. This Limestone is bioclastic in nature and is not of chemical origin as was thought by earlier workers.

The hitherto unreported foraminifera from the Nodular Limestone of Bilthana, consist of planktonic as well as benthic foraminifera. The former is represented by Heterohelix globulosa, while the latter represent the species of Lagenammina, Scherochorella, Ammobaculites, Haplophragmoides, Spiroplectammina, Trochammina, Textularia, Dentalina, Vaginulina and Frondicularia. The presence of simple Lituolid genera such as Ammobaculites, Haplophragmoides and Trochammina indicates prevalence of shallow water (within shelf condition) during the deposition of this limestone at Bilthana.