Many of the other collections from the Tuxedni formation in the Talkeetna Mountains that are listed below correlate with the Gaikema sandstone member or with the Red Glacier member as shown by the presence of Inoceramus lucifer Eichwald. This species at Wide Bay occurs as low as the base of the Kialagvik formation associated with ammonites of early Bajocian age. In the Cook Inlet area it ranges to the top of the Gaikema sandstone member and is associated in the upper part of its range (upper part of Red Glacier member and Gaikema sandstone member) with ammonites of early middle Bajocian age. In the Talkeetna Mountains such ammonites occur at Mes. locs. 3696, 3697, 8585, 24113, 24120, 24134, 24149, 24215, 24420, 25345, 25346, 25942, 25945, and 27577. These ammonites include in particular Sonninia, Witchellia, Papilliceras, Bradfordia, Otoites, Emileia, Labyrinthoceras, Skirroceras, Stephanoceras and Parabigotites. These in association are good evidence for correlating the beds in which they occur with the European zone of Otoites sauzei. Otoites and Labyrinthoceras are characteristic of that zone. Papilliceras, Witchellia and Bradfordia are not known above it. Stephanoceras and Emilea occur rarely below it in the upper part of the zone of Sonninia sowerbyi.

Please note that ammonites mentioned above do include Normannites, Chondroceras (except Mes. loc. 8567), Teloceras and Zemistephanus which are common in the Fitz Creek member of the Tuxedni formation at Cook Inlet. Also, note that the first three of these ammonites are characteristic of the European zone of Stephanoceras humprisianum.

Another item to note is that the Bajocian assemblages in the Talkeetna Mountains doe not include any genera typical of the European zone of Sonninia sowerbyi such as Docidoceras, Eumedtoceras, and Euhoploceras. This zone, likewise, has not been identified along Cook Inlet but is well developed at Wide Bay in the Alaskan Peninsula.

In summary the Bajocian ammonites from the Talkeetna Mountains show that lower, middle, and upper parts of the stage are represented but there is no positive evidence for the presence of beds equivalent to the European zones of Sonninia sowerbyi and Stephanoceras humphriesianum. The fossils from Mes. loc. 8567 could represent the last named zone, or the basal part of the upper Bajocian, or could be a mixture from a considerable thickness of beds, but its ammonite assemblage suggests an age slightly younger than that of the Fitz Creek member.

During the next few months I will be compiling distribution charts and maps and writing several chapters concerning the fossils. As these become available, copies will be sent to you and to Bob Detterman for your use and for criticism.

Jurassic ammonites of middle Bajocian age occur in the Tuxedni Group along the northwest side of Cook Inlet and in the Tuxedni Formation in the eastern part of the Talkeetna Mountain, Alaska. Numerically the dominant families are the Otoitidae and Stephanoceratidae. The families Phylloceratidae, Sonninidae, Oppelidae, and Perisphinctidae together compose only about one-third of the total specimens.

The Tuxedni Group has not furnished any ammonite genera that characterize the European zone of Sonninia sowerbyi at the base of the middle Bajocian. It has, however, furnished ammonites that characterize the next higher zones of Otoites sauzei and Stephanoceras humphriesianum.

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The exact stratigraphic position of most of the fossil collections within the silty part has not been determined. These include Mesozoic localities 8584, 8585, 24120, 24215, 24220, 25345, 25346, 25942 and probably 3696, 3697, and 8567. (from p. B10)

The Tuxedni Formation in the Boulder Creek area of the Talkeetna Mountains has yielded only two fossil collections. One (Mesozoic loc. 8572) contains an ammonite of late Bajocian age (Imlay, 1962b, p. 6). The other (Mesozoic loc. 8567) contains Normannites variabilis Imlay, n. sp. and Chondroceras allani (McLearn), which species in the Cook Inlet area occur togetherin the middle and upper parts of the Fitz Creek Siltstone. With these in the Boulder Creek area occurs the ammonite Leptosphinctes, which in Europe is characteristic of the late Bajocian. It is not known, however, whether the fossil from Mesozoic locality 8567 were collected from a few feet of beds or from a much greater thickness. Even if there if they were collected from a single bed, a correlation with the European zone of Stephanoceras humpriesianum is favored by the presence of Inoceramus ambiguus Eichwald shows that the beds containing these fossils are younger than the Gaikema Sandstone on Cook Inlet, which sandstone is correlated with the upper part of the Otoites sauzei zone. (from Imlay, 1964, p. B18)