Sample Detail of
Sample: Sample No. 75AMu57 -- USGS No. Mesozoic locs. D11071, D11072, D11073, D11074, D11075, D11076, D11077, D11078, D11079, D11080, D11081, D11082, D11083, D11084, D11085, D11086, D11087, D11088, D11089, D11090, D11091, D11092, D11093, D11094, D11095, D11096, D11097, D11098, D11099, D11100, D11101, D11102, D11103, D11104, D11105, D11106
Locality: Field No. 75AMu57
Description: Section located on bluff on east bank of Otuk Creek; sec. 31, T. 10 S., R. 16 W.
Location: Alaska Quadrangle: Killik River C-5
Township&Range: T10S R16W Section: Sec.31
Reference
Title: Report on Referred Fossils ,  1980 (04/01)
This report is concerned with 36 samples from different footages within the section selected as the type for the upper part of the Otuk Formation, a new name being proposed for the "Shublik Formation" in the overthrust sequences of the Brooks Range. Section located on bluff on east bank of Otuk Creek; sec. 31, T. 10 S., R. 16 W. Field no. 75AMu57.
Report by: Norman J. Silberling
Referred by: C. G. Mull
Age: Late Triassic
Formation: Otuk Formation
Comment:The collections marked with an * are the most age diagnostic for use in correlating this section.
Occurrence(s)
No. Group Name Qty Notes
1 Bivalves 114 ft.* - Monotis cf. M. subcircularis D11071 - early late Norian
2 Bivalves 113 ft. - Monotis cf. M. subcircularis D11072 - early late Norian
3 Bivalves 112 ft. - Monotis cf. M. subcircularis D11073 - early late Norian
4 Bivalves 111 ft. - ?Monotis cf. M. subcircularis D11074
5 Bivalves 110 ft. - ?Monotis cf. M. subcircularis D11075
6 Bivalves 109 ft. - ?Monotis cf. M. subcircularis D11076
7 Bivalves 108 ft.* - Monotis cf. M. subcircularis D11077 - early late Norian
8 Bivalves 107 ft. - ?Monotis cf. M. subcircularis D11078
9 Bivalves 106.5 ft. - Monotis sp. indet. D11079
10 Bivalves 106 ft. - Monotis sp. indet. D11080
11 Bivalves 105 ft. - Monotis sp. indet. D11081
12 Bivalves 102 ft.* - "Halobia cf. H. fallax" of Silberling, 1963 D11082 - late middle Norian
13 Bivalves Monotis sp. indet.
14 Bivalves 101.25 ft.* - Monotis (Eomonotis) pinensis D11083 - late middle Norian
15 Bivalves 101 ft. - "Halobia cf. H. fallax" of Silberling, 1963 D11084 - late middle Norian
16 Bivalves 98 ft. - Halobia sp. indet. D11085
17 Bivalves 96 ft. - Halobia sp. indet. D11086
18 Bivalves Monotis (Eomonotis) sp. indet. middle Norian
19 Bivalves 94 ft. - Halobia fallax Mojsisovics D11087 - middle Norian
20 Bivalves Halobia cf. H. lineata
21 Bivalves 90 ft. - ?Monotis (Eomonotis) sp. D11088
22 Bivalves 89 ft.* - Monotis (Eomonotis) sp. indet. D11089
23 Bivalves Halobia cf. H. fallax Mojsisovics D11089 - middle Norian
24 Bivalves ?"Halobia cf. H. fallax" of Silberling, 1963
25 Bivalves 88.5 ft. - Halobia sp. indet. D11090
26 Bivalves 87.5 ft.* - Halobia cf. H. fallax Mojsisovics D11091 - middle Norian
27 Bivalves "Halobia cf. H. fallax" of Silberling, 1963
28 Bivalves Halobia cf. H. plicosa
29 Bivalves 87 ft. - Halobia cf. H. fallax Mojsisovics D11092 - middle Norian
30 Bivalves "Halobia cf. H. fallax" of Silberling, 1963
31 Bivalves 78 ft. - Halobia cf. H. halorica D11093 - middle Norian
32 Bivalves 62 ft. - Halobia cf. H. lineata D11094
33 Bivalves 32 ft. - Halobia cf. H. lineata D11095
34 Bivalves ?Halobia cf. H. halorica D11095 - late early or middle Norian
35 Bivalves 31 ft. - ?Halobia cf. H. halorica D11096
36 Bivalves 27 ft.* - Halobia cf. H. dilitata D11097 - early Norian
37 Bivalves Halobia cf. H. cordillerana
38 Bivalves 25 ft.* - Halobia cf. H. dilitata D11098 - early Norian
39 Bivalves 18 ft. - Halobia sp. indet. D11099
40 Bivalves 13.5 ft.* - Halobia cordillerana D11100 - late Karnian - early Norian
41 Bivalves 13 ft. - Halobia cordillerana D11101 - late Karnia - early Norian
42 Bivalves 12 ft.* - Halobia cordillerana D11102 - late Karnian - early Norian
43 Bivalves 9 ft. - Halobia cf. H. cordillerana D11103
44 Bivalves 8 ft. - Halobia cf. H. cordillerana D11104
45 Bivalves 7 ft.* - Halobia zitteli or H. superba D11105 - late Karnian
46 Bivalves 5 ft.* - Halobia zitteli or H. superba D11106 - late Karnian

Title: The Late Triassic Bivalve Monotis in Accreted Terranes of Alaska ,  1997
ABSTRACT--Late Triassic bivalves of the genus Monotis occur in at least 16 of the lithotectonic terranes and subterranes that together comprise narly all of Alaska, and they also occur in the Upper Yukon region of Alaska where Triassic strata are regarded as representing non-accretionary North America. On the basis of collections made thus far, 14 kinds of Monotis that differ at the species or subspecies level can be recognized from Alaska. These are grouped into the subgenera Monotis (Monotis), M. (Pacimonotis), M. (Entomonotis), and M. Eomonotis. In places, Monotis shells of one kind or another occur in rock-forming abundance.

On the basis of superpositional data from Alaska, as well as from elsewhere in North America and Far Eastern Russia, at least four distinct biostratigraphical levels can be discriminated utilizing Monotis species. Different species of M. (Eomonotis) characterizes two middle Norian leves, both probably within the upper middle Norian Columbianus Ammonite Zone.
Report by: Norman J. Silberling , J. A. Grant-Mackie , K. M. Nichols
Age: Norian
Formation: Otuk Formation
Comment:[Silberling et al., 1997, p. 19 provides following description: Killik River region, northern Alaska; type section of Otuk Formation on bluff on east bank of Otuk Creek, D11071, 144 feet above base...Coll: C.G. Mull, 1975, field No. 75AMu57. Killik River 1:250,000 quadrangle (sec. 31, T. 10 S., R. 16 W.). [Endicott Mountains subterrane of the Arctic Alaska terrane]]