II.—A Contribution to the Molluscan Fauna of the Laki and Basal Khirthar Groups of the Indian Eocene

Abstract

The Tertiary geology of north-western India is of particular interest on account of the extensive development of richly fossiliferous rocks of Lower Eocene (including Palæocene) age. The monographs by Cossmann and Pissarro (1909a, 1927) and Vredenburg (1928) have familiarised us with the well-preserved molluscan fauna of the Upper Ranikot beds (Palæocene) of Sind, while Lt.-Col. L. M. Davies' collection of mollusca from a slightly lower horizon in the Samana Range, on the North-West Frontier, has recently been described by myself (1930). With the exception, however, of one family, the Gisortiidæ, dealt with by Vredenburg (1927) and Schilder (1930), the mollusea of the overlying Laki group (Ypresian), as well as of the Khirthar group (Middle Eocene), have been neglected by modern workers. The well-known monograph by D'Archiac and Haime (1853–54), moreover, in which some Laki species are described, has always been a source of confusion owing to the fact that fossils from all horizons from the Danian to the Miocene are grouped together as “Nummulitic,” and no reliable information as to their respective horizons has been available.

Some Eocene Cerithioids (Gastropoda, Mollusca) from Kutch, Western India, and Their Bearing on Palaeobiogeography of the Indian Subcontinent

“…The latter species also does not have any beaded ribs. Eames [31] reported two Stiracolpus species from the Eocene of Pakistan: S. pakistanica Eames 1952 and S. hernaiensis (Cox 1931). Both are comparable to the new Kutch species in many respects.…”

“…Faunas from Pakistan and western Indian basins have traditionally been considered together as the Indian fauna without much critical appreciation of these faunal compositions. This Indian fauna, during the Early Palaeogene, is known to be related most closely to the contemporaneous east African fauna [12,13,29]. This Indo-African fauna had affinity to faunas from the Middle East countries also [28,48].…”

“…The distribution of the cerithioid fauna from the Palaeocene and the Eocene of Pakistan reveals a similar picture. The cerithioid data has been collated from Cossmann and Pissarro [26], Vredenburg [38], Cox [28,29], Eames [31], and Iqbal [32][33][34]. Only 3 out of 48 species were known from outside Pakistan, 2 of which have wide geographical and temporal distributions.…”

“…The contemporaneous marine deposits from different parts of Pakistan have been known globally to yield a rich mollusc fauna including many cerithioids [25][26][27][28][29][30][31][32][33][34][35]. Because of geographical proximity the Kutch basin fauna has long been clubbed with the Pakistan fauna in the same palaeobiogeographical province without a critical assessment of the former.…”

Lower Paleogene Tectonostratigraphy of Balochistan: Evidence for Time-Transgressive Late Paleocene-Early Eocene Uplift

“…Foraminifera [52,[88][89][90][91][92], marine invertebrates [61,93,94] and vertebrate faunas [44,[95][96][97][98][99][100] from within and above the Ghazij Formation constrain its age to be latest Paleocene to early Eocene [95]. The Hunting Survey Corporation [52] collected the oldest fossils in the Ghazij Formation from a few feet above the basal unconformity near Umai and Zawar Kanr villages in the Kach area (see Figures A1-A3 for detailed locations).…”