of
Sample: Sample No. 57ADt10 -- USGS No. Mesozoic loc. 26596
Locality: Field No. 57ADt10
Description: "Fitz Creek" member of Tuxedni Formation. Upper part, but below 57ADt9. (description from Imlay E&R report of 1/22/58; Shipment A-58-1)[Transmittal sheet of Detterman, dated 12/18/57 provides following description: "Fitz Creek member; upper part but below 57ADt9; lithology similar; south shore Chinitna Bay; Coords: 13.6-15.75; 59o 48'30"N; 153o 07'25"W."][Shown as locality 107 on Pl. 3 of Detterman and Hartsock, 1966 - Note by R.B. Blodgett: digitization of this point gives approx. lat. 59o 48'52" N., 153o 06'22" W. - note this differs somewhat from the coordinates cited above that were given in Detterman's transmittal sheet.]
Location: Alaska Quadrangle: Iliamna D-1
Lat.: 59o48'30 " Long.: 153o07'25 "
Reference
Title: Report on Referred Fossils ,  1958 (01/22)
Your collections from the Gaikema member of the Tuxedni formation are rather meagre for an age determination. They contain, however, the same varied pelecypod faunule as has been found in other seasons. The collections made by Hartsock, Kellum, Kirschner, Miller and others suggest that the Gaikema member is equivalent to the lower part of the European zone of Otoites sauzei and that the underling siltstone member is equivalent to the zone of Sonnina sowerbyi.

The collections from the Fitz Creek member are excellent. They contain an assemblage that is correlated with the Otoites sauzei zone (See Arkell, 1956, Jurassic Geology of the World, p. 542).

The only other item of interest is your assignment of collection 57ADt13 to the basal part of the Naknek formation. The ammonites present, however, belong to a compressed subgenus of Cadoceras that is common in the upper part of the Chinitna formation on Chinitna Bay and Tuxedni Bay. This part of the Chinitna formation probably disappears southward toward Iniskin Bay. At least the ammonites from the top of the Chinitna formation near Iniskin Bay are identical with those found in the middle part of the formation on Chinitna Bay. You may want to check this relationship next summer.

Report by: Ralph W. Imlay
Referred by: Robert L. Detterman
Age: Jurassic (Jurassic, Otoites sauzei Zone)
Formation: Fitz Creek Siltstone ("Fitz Creek" member of Tuxedni Formation)
Comment:The collections from the Fitz Creek member are excellent. They contain an assemblage that is correlated with the Otoites sauzei zone (See Arkell, 1956, Jurassic Geology of the World, p. 542).
Occurrence(s)
No. Group Name Qty Notes
1 Ammonoids Sonninia sp.
2 Bivalves Inoceramus sp.
3 Bivalves Grammatodon sp.
4 Belemnites Belemnite fragment

Title: Geology of the Iniskin-Tuxedni Region, Alaska ,  1966
Report by: Robert L. Detterman , John K. Hartsock
Age: Bajocian (middle Bajocian)
Formation: Fitz Creek Siltstone
Comment:Geographic location: South shore of Chinitna Bay
Map reference (pl. 3): 107
Stratigraphic position below top of formation (ft): 1050-1100
all above data from Table 6, p. 33
Occurrence(s)
No. Group Name Qty Notes
1 Bivalves Grammatodon sp.
2 Bivalves Inoceramus sp.
3 Ammonoids Sonninia cf. S. tuxedniensis Imlay
4 Belemnites Belemnites