Collection part of scattered localities, statigraphic position determined by field-mapping correlations (from faunal list given on Table 2, pp. 8-9 in Campbell, 1967)

Fossil locality shown on Plate 1.

The Nasorak Formation (Campell, 1965a) is a limestone sequence named from typical exposures in sea cliffs near the mouth of Nasorak Creek (pl. 2B), where nearly 1,800 feet of the upper part of the formation are nearly contnuously exposed with relatively little structural complexity. (from Campbell, 1967, p. 7)

Fossils are relatively abundant. The identifiable forms are chiefly Bryozoa (predominately fenestrate), brachiopods, horn corals, lithostrotionoid corals, and a few endothyroid Foraminifera. The megafossils were examined by J.T. Dutro, Jr., and Helen M. Duncan, of the Geological Survey, who conclude (written commun., 1961) that collection from the upper 1,500 feet of the Nasorak Formation (table 2) indicate equivalence to the lower part of the Alapah Limestone (Upper Mississippian) of the central and eastern Brooks Range, and those from the lower approximately 500 feet indicate correlation with the upper part of the Wachsmuth Limestone (Lower Mississippian). They also conclude that the basal 165 feet of the Nasorak contains fossils that correlate with those of the Utukok Formation (Lower Mississippian) of the western DeLong Mountains (Sable and Dutro, 1961, p. 591-592) and that the fossils of the remaining 1,935 feet of the Nasorak are equivalent to those in part of the Kogruk Formation (Lower and Upper Mississippian) of the western DeLong Mountains (Sable and Dutro, 1961, p. 592). Apparently, then, the beds of the Nasorak Formation represent continuous deposition from Lower Mississippian at the base to Upper Mississippian at the top. The formation is accordingly assigned an Early and Late Mississippian age; the lower member and Cape Thompson Member are included in the Lower Mississippian part, and the boundary betweeen the Lower and Upper Mississippian lies in the lower part of the upper member. (from Campbell, 1957, p. 14)

Collection 58ACr36 contains two poorly brachiopods, Linoproductus? sp. and a large indeterminate spiriferoid, of types not ordinarily found in the Utukok formation in the Brooks Range. A Late Mississippian age is suggested for this collection as well.

Both collections consist of a rock type common in the Alapah limestone, in various places, and separately mapped as the Tupik formation (name not yet published) in the DeLong Mtns.