In general, the sequence of faunas is consistent with those found in the measured sections. All collections from unit Ml₄ can be correlated with the upper Alapah faunas. Collections 133, 147 and 59ACu15 represent the "Chester"-type assemblage, also found in collection 55 of the measured section. It would appear that 59ACu15 may be correlated too high in the unit.

Collection 138 seems to be out of place. The distinctive Spirifer that occurs in abundance in this collection is found in the central Brooks Range in rocks of Wachsmuth age.

The group of collections that were listed as either Ml₃ or Ml₁ probably should be assigned to Ml₁. The fossil assemblage of 59ACr 19-20 is very like that of 119 which characterizes Ml₁ in the measured section.

Collection 15 contains a Wachsmuth age assemblage and therefore contributes evidence for the Wachsmuth equivalence of unit Ml₂. In the measured sequence, Ml₂ did not contain definitive fossils but was bracketed by upper Wachsmuth fossil assemblages in Ml₁ and lower Ml₃.

Collections 162 and 154 present a problem. The corals in these collections suggest a higher position in the section than indicated on the transmittal sheets. Faberophyllum? was found in collection 27 and may tie that collection to 162. On the other hand, the brachiopods suggest a lower correlation. Collection 154 may correlate with the levels of collections 8 or 1 in the measured section. These two collections (162 and 154) seem to have been collected at the place where I made extensive collections and measured a section in 1951. It was my opinion, at the time, that the sequence in that area should be correlated much higher (perhaps with your unit Ml₄). The coral-bearing beds are overlain by quite a thickness of dolomites. What I consider good evidence of faulting would explain the juxtaposition over beds equivalent to your Ml₁.

In this report we have labeled the larger animal groups where any confusion might exist. In this, as well as earlier reports, the fossils are listed in systematic order.

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 name Kogruk(?) Formation is applied to thick dolomitic section (unit Ml₄ of Campbell 1960a, b) in the Lisburne Group of this area because its stratigraphic position is similar to that of the Kogruk Formation as described by Sable and Dutro (1961, p. 592) in its type area in the western DeLong Mountains (from Campbell, 1967, p. 14)

Fossil material consists of abundant crinoid columnals and undetermined echinoderm debris and subordinate Bryozoa, horn corals, small colonial corals (including lithostrotionoid corals, particularly near the base), brachiopods of several species, and at least one blastoid (table 2). The fossil collections were examined by J.T. Dutro, Jr., and Helen M. Duncan, of the Geological Survey, who report (written commun., 1961) that the fossils appear to correlate with those in the upper part of the Alapah Limestone of the central Brooks Range. Several collections represent a Chester-type assemblage of bryozoans, brachiopods, and echinoderms. Dutro and Duncan also note that the collections correlate broadly with the Gigantoproductus zone of the central Brooks Range and that Gigantoproductus has been found in similar rocks near Cape Lisburne. They further suggest (written commun., 1961) that the Kogruk(?) Formation and most of the underlying Nasorak Formation are faunally equivalent to the type Kogruk of the western DeLong Mountains. The presence of Late Mississippian fossils in the Kogruk(?) and in the upper part of the underlying Nasorak Formation suggest that all the rocks assigned to the Kogruk(?) in this area are of Late Mississippian age, whereas the type Kogruk Formation of the western DeLong Mountains is considered to be of Early and Late Mississippian age (Sable and Dutro, 1961, p. 592). (from Campbell, 1967, p. 18)