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Report on Referred Fossils
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Stratigraphic range: Upper Jurassic and Upper Cretaceous
Kinds of fossils: Mollusks
Quadrangle or area: , Alaska Peninsula-Katma
Shipment No.: A-54-12
Referred by: Keller, A. S.
Report prepared by: Imlay, Ralph W.
Date: 11/08/1954

The fossils from the Naknek formation belong in the zone of Aucella rugosa (Fischer). There is no representative of the older zone characterized by Aucella concentrica (Fischer)(equals A. bronni or the still older zone characterized by species of Cardioceras. The latter has never been found on the Alaska Peninsula, but the zone of A. concentrica is widespread. In the Talkeetna Mountains the base of the zone with Aucella rugosa is near the middle of the Naknek in the southern exposures but occupies the base of the formation in the northernmost exposures. Similar overlap relationships should be considered in future field work on the Naknek formation of the Alaska Peninsula.

The fossils from the Kaguyak formation are of Campanian or Maestrichtian age and are younger than any fossils found in the Chignik formation in the southern part of the Alaska Peninsula. In the Talkeetna Mountains fossils identical with those in the Kaguyak formation occur at the top of the siltstone member of the Matanuska formation just below the highest sandstone member. The smooth compressed pachydiscid ammonite from locality 54AKe41 is good evidence of a postion high in the Upper Cretaceous sequence. The small Inoceramus with sharp, equally-spaced ribbing that is compared with I. kusiorensis Nagao and Matumoto is likewise common the high Cretaceous beds.

Several years ago I examined an excellent collection from the Kaguyak area made by John Hazzard and associates of the Union Oil Company. A copy of that report can be sent to you if you so desire.

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54AKe1 (Mesozoic loc. 25276) , Mt Katmai , 170 to 230 feet above the top of Chisik conglomerate. Northeast side of Grosvenor Lake, Lat. 58 deg. 41' N., Long. 155 deg. 07' W., Alaskan Peninsula (from E&R report); USGS Mesozoic locs. 25276-25278 and M 2076. On northeast side of Grosvenor Lake, lat 58°41' N., long 155°7'-10' W., Mt. Katmai quadrangle, Alaska Peninsula. Buchia rugosa (Fischer) and B. mosquensis (von Buch) range from just below Chisik Conglomerate Member of Naknek Formation (loc. M 2076) to 530 feet above (loc. 25277). (description from Imlay and Detterman, 1973, p. 27);[USGS Mes. Cat.: 25276. 54AKe1. Upper Jurassic, Naknek Formation, 170' to 230' above top of Chisik cg. in green to light gray arkosic ss. Lat. 58°41' N., Long. 155° 07' W., northeast of Grosvenor Lake, Katmai quad, Subdivision C4., Alaskan Peninsula, Alaska]
Aucella rugosa (Fischer)
Aucella mosquensis (von Buch) (common)
Meleagrinella sp.
54AKe2 (Mesozoic loc. 25277) , Mt Katmai , 500 to 530 feet above top of Chisik conglomerate on northeast side of Grosvenor Lake. Lat. 58 deg. 41' N., Long. 155 deg. 07' W. (from E&R report); USGS Mesozoic locs. 25276-25278 and M 2076. On northeast side of Grosvenor Lake, lat 58°41' N., long 155°7'-10' W., Mt. Katmai quadrangle, Alaska Peninsula. Buchia rugosa (Fischer) and B. mosquensis (von Buch) range from just below Chisik Conglomerate Member of Naknek Formation (loc. M 2076) to 530 feet above (loc. 25277). (description from Imlay and Detterman, 1973, p. 27); [USGS Mes. Cat.: 25277. 54AKe. Upper Jurassic. Naknek Fm. 500' to 530' above top of Chisik cgl. at same loc. as 25276]
Aucella rugosa (Fischer) (common)
Aucella mosquensis (von Buch)
Pleuromya sp.
54AKe3 (Mesozoic loc. 25278) , Mt Katmai , 0 to 80 feet above top of Chisik conglomerate on northeast side of Grosvenor Lake. Lat. 58 deg. 41' N., Long. 155 deg. 10' W. (from E&R report); USGS Mesozoic locs. 25276-25278 and M 2076. On northeast side of Grosvenor Lake, lat 58°41' N., long 155°7'-10' W., Mt. Katmai quadrangle, Alaska Peninsula. Buchia rugosa (Fischer) and B. mosquensis (von Buch) range from just below Chisik Conglomerate Member of Naknek Formation (loc. M 2076) to 530 feet above (loc. 25277). (description from Imlay and Detterman, 1973, p. 27); [USGS Mes. Cat.: 24278. 54AKe3, Upper Jurassic, Naknek Fm. 0' to 80' above top of Chisik cg. On small stream on northeast side of Grosvenor Lake, Lat. 58°41' N., Long. 155°10' W. Katmai quad., Subdivision 4. Alaskan Peninsula, Alaska.]
Aucella mosquensis (von Buch) (common)
Aucella rugosa (Fischer)
Pleuromya sp.
54AKe4 (Mesozoic loc. 25279) , Mt Katmai , From sandstone, siltstone and conglomerate in lower part of Naknek formation, Lat. 58 deg. 40' N., Long. 155 deg. 13' W., just east of reverse fault on south side of Grosvenor Lake.
Aucella mosquensis (von Buch)
Rhynchonellid brachiopods
54AKe40 (Mesozoic loc. 25280) , Afognak , About 300 feet above contact with Naknek formation in cutbanks along coast north of Kaguyak, Lat. 58 deg. 37' N., Long. 153 deg. 55' W., Alaskan Peninsula.
Inoceramus spp.
Pleuromya? sp.
54AKe41 (Mesozoic loc. 25281) , Afognak , Between 900 and 1000 feet above contact with Naknek formation at same loc. as 54AKe40
Pachydiscus (Neodesmoceras) sp.
Inoceramus cf. I. kusiroensis Nagao and Matumoto
Nemadon sp.
Anomia cf. vancouverensis Gabb
54AKe42 (Mesozoic loc. 24282) , Afognak , About 1300 to 1500 feet above contact with Naknek formation at same locality as 54AKe40.
Lytoceras (Gaudryceras) sp.
54AKe43 (Mesozoic loc. 25283) , Afognak , About 1500 to 1700 feet above contact with Naknek formation at same locality as 54AKe40.
Inoceramus cf. I. kusiroensis Nagao and Matumoto
Inoceramus cf. I. shikotanensis Nagao and Matumoto