Abstract

Devonian rocks on the Indo-Pakistan subcontinent crop out in the high mountains and the foothills of the Hindu Kush, Karakoram, and Himalayan Ranges that border the Indian peninsula.

Fossil assemblages of Devonian or Silurian-Devonian age have been collected from three localities, all in northern Pakistan: near the village of Reshun in Chitral State, from Boroghil Pass near the Afghan border, and recently from hills near the town of Nowshera 25 miles due east of Peshawar. Sparsely fossiliferous rocks believed to be Devonian in age include limestones and shales near Swabi and carbonates in the Saidu and Abbottabad areas. Rocks correlated as Devonian by their stratigraphic position or lithological similarity to known Devonian outcrops include carbonates and slates in the Khyber Pass area and the scarp-forming Muth quartzite, which extends from the Srinagar area of Kashmir southeast beyond Muth and the Spiti River.

Devonian outcrops consist mainly of limestone, dolomite, and quartzite. Carbonate rocks in at least one area (Nowshera) represent a reef complex, whose individual reef cores have faunal zones or layers interpreted as representing a gradual upward growth of the reef mass from calm into turbulent water. Fragments of reef breccia have been collected near Swabi and northeast of Reshun.

The apparently widespread distribution of reef carbonates and associated quartzites suggests that during the Devonian Period much of northern Pakistan and India was probably covered by warm shallow seas.