This report covers 24 collections made from Permian and related rocks in the northeastern Brooks Range during the summer of 1970. Most of the collections (18) are from the Echooka member of the Sadlerochit Formation and they contain elements of the Arctic Permian fauna that has been reported in previous years. The characteristic species of this assemblage are widely distributed in younger Permian strata throughout the Arctic region. Perhaps the most complete documentation of this fauna is that of Gobbett (1963) from the Brachiopod Chert of Spitzbergen. In terms of the west Texas sequence, the Arctic Permian fauna is either a late Word or early Guadalupe equivalent. Most European workers have correlated in with the Kazanian (early Late Permian)

Of considerable interest is a sequence of collections from south of Wahoo Lake (70Adt225, units 1-8). At this locality, which is very near the type locality of the Wahoo Limestone, about two hundred feet of carbonate rocks just below the base of the Sadlerochit Formation are quite fossiliferous. By original definition these are a part of the Wahoo Limestone. In the original fossil material from this area, only sparse brachiopod faunas were collected from the Wahoo. A definite age for the upper part of the Wahoo was not given, although brachiopods at the very top were reported by Dutro to be like those of the basal Sadlerochit (Permian) and a small assemblage from 400-500 feet below the top of the formation was considered Pennsylvanian(?).

The collections reported here give the first definite evidence of a middle or late Pennsylvanian megafauna from the Wahoo Limestone. Among the brachiopods, several species have been reported from pre-Permian strata in Spitzbergen. Most characteristic of these is Laevicamera arctica (Holtedahl) which occurs in the Middle and Upper Carboniferous in Spitzbergen. Similar species have also been reported from the Moscovian of northern Russia. Also common is Choristites, a characteristic Middle and Upper Carboniferous genus in the old world and northern regions. It should be noted that specimens of Waagenoconcha, Horridonia? and Spiriferella? also occur in these collections from the upper Wahoo Limestone. These genera are known elsewhere from the Upper Carboniferous, as well as from the Echooka Member, and care must be taken to evaluate the entire assemblage before ascribing a Permian age on the basis of a few specimens.

Foraminifera from this sequence have been examined by B.L. Mamet, Unit. Of Montreal, who has identified Zones 21-22+- (Desmoines equivalent) in the lower three units of the sequence; this includes about 75 feet of beds.

The rest of the pre-Permian could either be Middle or Late Pennsylvanian, but I feel that there is a definite faunal break in the sequence below unit 11 which has a characteristic Echooka fauna.

This suggests that even in the thickest sequences of the Wahoo Limestone, in the vicinity of Wahoo Lake, there is a disconformity with most of the lower Permian and, perhaps, part of the late Pennsylvanian missing.

Permian

Most of the collections are characteristic of the fauna in the lower part of the Echooka Member; perhaps the most persistent element in this assemblage is the genus Megousia. Four collections (189-4, 193-11, 196-3 and 204-1) contain elements of a restricted fauna that may be useful for correlating among the four sections. Two collections from higher in the member (189-7 and 196-7) have very spares faunas that are, although late Permian, atypical.

The occurrence of the typical lower Echooka fauna at 175-202 feet in the Aichillik River section is noteworthy and may indicate a thickening of the lower Echooka eastward.

In view of the interest in pelecypod prisms in Permian rocks, special attention should be called to collection 196-3, from the Pogopuk Creek section, which contains abundant shell fragments composed of prisms.

The enclosed distribution chart for the Permian collections was prepared by David Bieler during his winter term in Washington. In addition, much of the preparation was done and preliminary identifications were made by Bieler. On the chart, relative abundance is indicated as follow: species present –x; rare (2-5 specimens) – r; common (6-12 specimens) – c; abundant (>12 specimens) – a; species questionably identified - ?.

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Brief statement of problem and remarks (from collector):
Most of the collections are from measured sections, and we need the fossils to understand the depositional environment and relationship to underlying and overlying rocks. The Permian part of the Wahoo section at Wahoo Lake are included.