Reference Detail of

Report on Referred Fossils
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Stratigraphic range: Upper Jurassic
Kinds of fossils: Mollusks
Quadrangle or area: Iliamna A-3 and B-3 quads, Head of Alaska Peninsula
Shipment No.: A-67-20
Referred by: Detterman, Robert L.
Report prepared by: Imlay, Ralph W.
Date: 12/05/1967

The only fossils of age significance in these collections are Buchia concentria (Sowerby) and B. rugosa (Fischer) whose ranges are known to you from earlier reports. The association of these species at loc. 67ADt1529 indicates a middle Kimmeridgian age. The occurrence of B. rugosa by iteself indicates a middle Kimmeridgian to early Portlandian age.

Recent collections submitted by Standard Oil Co. of Calif. from the Staniukovitch Formation contain Buchia uncitoides (Pavlow) and B. crassicollis (Keserling) subspecies solida (Lahusen), which species are respectively of Berriasian and Valanginian ages. The identifications made by David Jones for C. A. Burk (1965, G.S.A. Mem. 99, p. 219) need rechecking because at the time Dave made those identifications he did not differentiate B. uncitoides from B. piochii (Gabb). As your collections do not contain anything resembling B. piochii or B. uncitoides, it seems doubtful that any part of the Naknek Formation in your map area is as young as the Staniukovitch Formation.


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Brief statement of problem and remarks (from collector):
These specimens are from high in the Naknek Fm.; believed to be younger than anything exposed on Inishin Peninsula. They are close to possible contact with Lower Cretaceous and probably equivalent to Burk's Staniukovich Fm. on Alaska Peninsula.
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67ADt1421 , Iliamna , Dark-blue gray siltstone overlying massive cobble-boulder conglomerate just east of Bruin Bay Fault. May correlate with Snug Harbor siltstone. Sea cliffs near Fortification Bluff. 5.5 miles N. 55 deg. E. of north point at mouth of Bruin Bay. Lat. 59 deg. 25'20" N., long. 153 deg. 51' W.
Belemnite guard undet.
67ADt1422 , Iliamna , Massive to thin bedded greenish-gray to yellowish siltstone at west end of Fortification Bluff; 6 miels N. 60 deg. E. of north point at Bruin Bay; lat. 59 deg. 25'15" N., long. 153 deg. 50'30"
Pleuromya sp.
67ADt1517A , Iliamna , Interbedded sandstone and siltstone with shell beds near synclinal axis - very high in Naknek Fm. Sea cliffs on north shore Kamishak Bay; 6 miles west of mouth of Douglas River; lat. 59 deg. 03'45" N., long. 153 deg. 55'45" W.
Buchia rugosa (Fischer)
67ADt1518A , Iliamna , Massive, cross-bedded arkosic pebbly sandstone with siltstone interbeds; lower in section than 1517A; 1.9 miles N. 70 deg. W. of mouth of Douglas River. Lat. 59 deg. 04'15" N., long. 153 deg. 48'45" W.
Tancredia or....
.... Quenstedtia
67ADt1520A , Iliamna , Massive, light-gray arkosic sandstone, cross-bedded, 100-foot thick unit, higher than 1518A; 2.3 miles N. 85 deg. W. of mouth of Douglas River; lat. 59 deg. 04' N., long. 153 deg. 49'30" W.
Pachyteuthis? sp.
Tancredia? sp.
67ADt1520B , Iliamna , Same locality in medium bedded sandstone and siltstone about 150 feet above 1520A.
Meleagrinella sp.
Buchia rugosa (Fischer)
67ADt1529 , Iliamna , Massive, yellowish gray, medium grained, argillaceous sandstone near west end of bluffs 9.8 miles N. 85 deg. W. of mouth of Douglas River. Lat. 59 deg. 04'30" N., long. 154 deg. 02' W.
Buchia rugosa (Fischer)
Buchia concentrica (Sowerby)
67ADt1532 , Iliamna , Interbedded sandstone and siltstone near base of 800-foot bluff section; 8 miles N. 85 deg. W. of mouth of Douglas River; Lat. 59 deg. 04'15" N., long. 154 deg. 00' W.
Cylindroteuthis? sp.
67ADt1536 , Iliamna , Interbedded sandstone and siltstone with limestone lenses and concretions; higher in section than 1517A; 4 miles S. 80 deg. W. of mouth of Douglas River; Lat. 59 deg. 03' N., long. 153 deg. 52'15" W.
Macrophylloceras sp.
Pleuromya sp.
Buchia cf. B. mosquensis (von Buch)
Buchia sp. undet.
67ADt1537 , Iliamna , Dark greenish yellow siltstone with sandstone interbeds and limestone concretions about 500-600 feet higher than 1563; 4.3 miles S. 75 deg. W. of mouth of Douglas River; Lat. 59 deg. 02'45" N., long. 153 deg. 52'30" W.
Phylloceras sp.
Macrophylloceras sp.
Buchia rugosa (Fischer)
Buchia cf. B. mosquensis (von Buch)