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Reference
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| Title: |
Report on Referred Fossils
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1961
(02/24)
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| Report by: |
Norman J. Silberling
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| Referred by: |
C. L. Whittington
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| | Age: | Norian |
| Formation: | Shublik Formation (Sandstone (siltstone) member of Shublik Formation) |
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| Comment: | These collections (48AWh63, 90, 101, 124, 138, 48ASa19, 99, 20, 113, 118, 124), well located both geographically and stratigraphically, provide a nice sample of the fauna of the Shublik formation in northeastern Alaska. Owing partly to a lack of described comparative material and partly to poor preservation, most of the collections lack specimens with independent age significance. Fortunately, critical dating fossils do occur in collections from both the lower and upper parts of the formation, and several of the collections can be related to one another and to previous collections of known age by the mutual occurrence of distinctive, though unnamed, forms. A middle or late Norian (late Late Triassic) age is suggested for the entire Shublik formation in this part of Alaska; evidently none of your collections are as old as Karnian, the age suggested for part of the Shublik by Martin (Bull. 776, p.105). The occurrence of MONOTIS cf. M. SUBCIRCULARIS, a reliable marker for the middle or upper Norian, in 48Awh63 from the basal sandstone member indicates that you are correct in excluding these rocks from the underlying Sadlerochit formation. The gastropod, characterized by “type A”, in 48Awh63A is also present in your collections from the limestone member and suggests not much difference in age between the two members. This same gastropod occurs with STEINMANNITES?, a Norian ammonites, and MONOTIS in Sable’s collection 58Asa83, reported on previously from the Mt. Michelson quadrangle. HALOBIA, like H. CORDILLERANA Smith, commonly occurs in rocks interbedded with those bearing MONOTIS in Alaska. 48Asa118 from the top of the formation is related by “SPIRIFERINA” sp. “B” to 48Asa113 which was collected as float a few feet lower and which can be dated as middle or late Norian by the presence of MONOTIS. Collections 48Asa98, 48Asa121 and 48Asa127 were not received. |
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