Reference Detail of

Report on Referred Fossils
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Stratigraphic range: Cretaceous
Kinds of fossils: Mollusks
Quadrangle or area: Mt. Michelson and Demarcation Point
Shipment No.: A-72-15M
Referred by: Detterman, Robert L.
Report prepared by: Jones, David L.
Date: 11/02/1972

This report covers collections from Ignek Creek and Demarcation Point quad. The most significant fossils are those of Hauterivian age - the first recorded from northern Alaska. Coll: R.L. Detterman, 1971.


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Brief statement of problem and remarks (from collector):
Most of the specimens are from a dark manganiferous siltstone and shale unit that is widespread in northern Alaska; these are the first fossils found in this unit.

Two collections from Leffingwell's type Ignek section.
User Note module to be added
71ADt288 unit 4 (Mesozoic loc. M5813) , Mt Michelson , Ignek Creek, Mt. Michelson Quad. - north side of stream 3.6 miles N. 83 degrees E. of mouth of stream - dark silty pebble shale. Lat. 69 deg. 36' N., long. 146 deg. 08'30" W. (description from transmittal sheet of Detterman for Jones E&R report)[Detterman's transmittal sheet for microfossil analysis, dated Jan. 6, 1972, cites this locality as a "silty pebble shale section, Lower Cretaceous"]
Aptychus?
tiny pectinid clams
other indeterminable small clams
tubes of unknown origin
71ADt 288 unit 5 (Mesozoic loc. M5814) , Mt Michelson , Ignek Creek - north side, 4.0 miles N. 83 deg. E. of stream mouth; dark silty pebbly sandstone, underlies unit 4. Lat. 69 deg. 36'05" N., long. 146 deg. 07'30" W. (description from transmittal sheet of Detterman)
indeterminable clam
71ADt313 (Mesozoic loc. M5815) , Demarcation Point , Demarcation Point Quad. Ridge top 7.75 miles N. 24 deg. W. of point where Kongakut River crosses into Table Mountain Quad. Lat. 69 deg. 06'10" N., long. 142 deg. 17' W. Dark, hackly fracturing siltstone and shale with ironstone concretions about 700 feet west above the coquina zone. (description from transmittal sheet of Detterman)
Aucellina (?) scraps
71ADt314A (Mesozoic loc. M5816) , Demarcation Point , Ridge 8 miles N. 22 deg. W. of point where Kongakut River crosses into Table Mountain Quad., Lat. 69 deg. 06'20" N., long. 142 deg. 16'45" W.; dark manganiferous siltstone and shale with pebbles about 370 feet above coquina zone. (description from transmittal sheet of Detterman)
Branching tubes of unknown origin
71ADt314B (Mesozoic loc. M5817) , Demarcation Point , Same as 314A. Gray siltstone and shale with sandstone interbeds, few ironstone nodules and pebbles about 255 feet above coquina zone. (description from transmittal sheet of Detterman [Jones E&R provides following description: "Demarcation Point. Same locality as M5816, but 15 ft lower in section."]
Crushed fragments of Simbirskites sp. indet.
Crushed and silicified belemnites
Fragments of Lytoceras sp.
brachiopod
71ADt315 (Mesozoic loc. M5818) , Demarcation Point , Kongakut River area, 7.5 miles N. 18 deg. W. of where river crosses into Table Mt. Quad., Lat. 69 deg. 06'15" N., long. 142 deg. 15' W. Coquina zone in sandstone and shale section. (description from transmittal sheet of Detterman)
Coquina of Buchia sublaevis Keyserling