Early Ordovician and Devonian conodonts from the western Karakoram and Hindu Kush, northernmost Pakistan

Extensive tracts of Devonian and older sedimentary and igneous units occur within the axial region of the western Karakoram Block of northernmost Paki stan over a distance in excess of 200 km between the the headwaters of the Karambar valley in northwestern Gilgit Agency to southwestern Chitral. Cono dont data indicate that the oldest sedimentary unit so far discriminated wi thin this belt, the Yarkhun Formation, includes horizons of Ordovician (Are nig) age, consistent with an earlier-presented acritarch-based Arenig age f or part of the same unit. Conodont data from the "Lun Shales", a stratigrap hic potpourri with little-known Silurian and Devonian tracts, demonstrate t he presence of Early Devonian (early Emsian) horizons. The Shogr (a) over b ar m Formation, widely distributed through the region, spans an appreciable interval of the Middle and Late Delacuna in sedimentation may be present, represented by all or most of the earlier half of Frasnian time. A biostrat igraphically and possibly biogeographically important new species, Icriodus homeomorphus, is described; it is encountered in horizons of early Famenni an age (Late triangularis Zone to ?Early crepida Zone).