Table 1: Age assignments for Usfan Formation by previous authors and the present work.

Author

Age

Tools used

Karpoff [1]

Late Maastrichtian - Eocene

Molluscs and shark teeth

Al-Shanti [4]

early Eocene

Mollusca

Brown [10]

43-55 Ma (Eocene)

K-Ar dating

Basahel, et al. [11]

Maastrichtian

Nautiloids and bivalves

Moore and Al-Rehaili [12]

Paleocene to Early Eocene

Stratigraphic position

Abou Auf and Gheith [13]

Maastrichtian to Eocene

Radiometric and Biostratigraphic evidence

Present work

Cenomanian-Turonian

Molluscs