Reference Detail of

Report on Referred Fossils
Edit Reference Add/Edit Sample Sample List Show Map

Stratigraphic range: Upper Jurassic
Kinds of fossils: Ammonites
Quadrangle or area: Sutwik Is. D-5, Chignik B-2, B-3, Alaska
Shipment No.: A-97-32
Referred by: Detterman, Robert L.
Report prepared by: Imlay, Ralph W.
Date: 07/23/1979

Among the ammonites listed on this report, Phylloceras (Partschiceras) sp. B occurs at three localities. It has been collected previously only on the Alaska Peninisula and only at Mesozoic localities 11359 (Chignik D-1 quad.) and 29253 (Iliamna A-3 quad.) At Mesozoic loc. 29253 at Kamishak Bay it was associated with Buchia mosquensis (von Buch), a species of late Kimmeridgian and early Tithonian age.
The ammonite from loc. M6914 listed as Discosphinctes? sp. juv. is probably an immature form of Discosphinctes (See Treatise by Arkell and others, 1957, p. L320, L322) of late Oxfordian age. It is common in the Tethyan region but has been found as far north as California (See Prof. Paper 374-D, p. D5, D7, D13, D23, pl. 3, figs. 1-12). The adult form of Discosphinctes differs from the immature form by developing more secondary ribs per primary rib. It is probably too late to include a picture of the ammonite from locality M6914 in my paper on Upper Jurassic Ammonites From Alaska but that possibility will be considered.
I notice that none of the ammonite collections that you made on the Alaska Peninsula in 1977 include any specimens of Buchia. Such should be included in the future if Buchia occurs in, or within a few feet of a bed containing ammonites. Also, a collection of buchias from above a bed containing some ammonites might be useful as additional age evidence. In this regard, please note that Discosphinctes in California occurs in beds containing Buchia concentrica and has never been found associated with B. rugosa, or B. mosquensis.

User Note module to be added
77ADt27 (Mesozoic loc. M6910) , Sutwik Island , Sutwik Island (D-5) Quadrangle. Latitude 56 deg. 56 min. 23sec. N; Longitude 157 deg. 23 min. 27 sec. W. Section 34, T. 37 S., R. 51 W., 5.1 mile N. 8 deg. E. of mouth of Northeast Creek. Naknek Formation, dark siltstone sequence. Coll. R. L. Detterman, 1977.
Phylloceras (Partschiceras) sp. B
77ADt113 (Mesozoic loc. M6914) , Chignik , Chignik (B-2) Quadrangle. lat. 56 deg. 28'12" N., long. 158 deg. 31'17On ridge south of Thompson Valley, 4.5 miles N. 72 deg. W. of stream mouth. Naknek Formation, massive grit and sandstone. Co... R. L. Detterman, 1977.
Discosphinctes? sp. juv.
77ADt119 (Mesozoic loc. M6916) , Chignik , Chignik (B-3) Quadrangle. Latitude 56 deg. 18 min. 42 sec. N; Longitude 158 deg. 41 min. 35 sec. W. Section 5, T. 45 S., R. 60 W., 3.5 miles S. 85 deg. W. of Chignik Lagoon Cannery. Naknek Formation, interbedded thin sandstone and siltstone. Coll. R. L. Detterman, 1977.
Ammonite venter. Genus not determinable
77ADt120 (Mesozoic loc. M6917) , Chignik , 2.5 miles S. 75 deg. W. of Chignik Lagoon Cannery on same ridge as loc. M6916. Naknek Formation, siltstone and limestone about 400 feet stratigraphically higher than ADt-119. Coll. by R. L. Detterman, 1977.
Ammonite fraqment
77ADt121 (Mesozoic loc. M6918) , Chignik , Same location as M6917 except 0.3 mile east along ridge and about 180-200 feet higher. Naknek Formation, feldspathic sandstone. Coll. R. L. Detterman, 1977.
Phylloceras (Partschiceras) sp. B
77ARh40A (Mesozoic loc. M6921) , Chignik , Chignik (B-2) Quadrangle. Latitude 56 deg. 22 min. 44 sec. N; Longitude 158 deg. 30 min. 12 sec. W. Section 13, T. 44 S., R. 59 W., sea cliff 1.3 miles north of triangulation station Chignik Bay West Base. Naknek Formation, interbedded siltstone and silty gray sandstone. Coll. R. L. Detterman, 1977.
Phylloceras (Partschiceras) sp. B