Albian ammonites from northern Pakistan

Abstract

The occurrence of rich Albian ammonite faunas in what is now northern Pakistan has been known for more than 80 years, but there has been no comprehensive account of the assemblages present. A total of 36 taxa are described below. The middle part of the Lumshiwal Formation yields Upper Aptian ammonites south of the Samana Range. Elsewhere, it yields Douvilleiceras leightonense Casey, 1962, of the lower Lower Albian Leymeriella regularis Zone and the Sonneratia perinflata and S. kitchini Subzones of the Sonneratia chalensis Zone of the northwest European sequence. The top one to two metres of the Lumshiwal yields an abundant fauna of rolled and phosphatised ammonites that includes elements from much of the Albian. Of these, Prolyelliceras gevreyi (Jacob, 1907) first appears in the lower Lower Albian Leymeriella tardefurcata Zone. The commonest ammonite is Douvilleiceras mammillatum (Schlotheim, 1813) sensu lato, which ranges from the perinflata Subzone of the chalensis Zone to the Otohoplites bulliensis Subzone of the O. auritiformis Zone of the Lower Albian. The presence of Lyelliceras pseudolyelli (Parona and Bonarelli, 1897) indicates the uppermost, pseudolyelli Subzone of the auritiformis Zone. The presence of Lyelliceras lyelli (d’Orbigny, 1841) indicates the basal Middle Albian lyelli Subzone of the Hoplites dentatus Zone. There is no evidence for the higher parts of the Middle Albian. Dipoloceras (Rhytidoceras) sp. indicates the presence of lower Upper Albian, possibly the pricei Zone. There is evidence, in the form of specifically indeterminate Mortoniceras (Mortoniceras) sp., of a level within the inflatum to fallax Zone inteval from a single locality, but no evidence of the succeeding parts of the upper Upper Albian. The base of the Kawagarth Formation that succeeds the Lumshiwal yields lower Upper Albian Mortoniceras (M.) geometricum Spath, 1932 of the Mortoniceras pricei Zone, northwest of Darmasand in the Samana range.