Report on Referred Fossils |
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| Stratigraphic range: |
Jurassic-Cretaceous |
| Kinds of fossils: |
Mollusks |
| Quadrangle or area: |
Sitka B-6 quad. |
| Shipment No.: |
A-61-17M |
| Referred by: |
Pomeroy, J. S.
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| Report prepared by: |
Jones, David L.
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| Date: |
09/22/1961 |
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This reports covers fossils from Southeastern Alaska, Admiralty Island, collected in 1961. Older collections from the same area, as well as elsewhere in Southwest Alaska, are also included. The only significant fossils present are Aucellas, and these appear to be of Late Jurassic and earliest Cretaceous age. Preservation of many collections is poor, and specific identification is at best a guess.
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***
Brief statement of problem and remarks (from collector):
In 1917, R.M. Overbeck collected fossils along the west side of Slocum Arm (U.S. Geol. Survey Bull. 692-B, 1919). Two of the above localities (61APy575F and 61APy584F) are believed to be identical with Overbeck's 17AOF8 and 17AOF7 stations respectively. Stanton believed these rocks to be probably Upper Jurassic (p. 108) but did not preclude the possibility that they might be Lower Cretaceous. A reappraisal is needed at this time not only for the above two localities but for two others (61APy567F and 61APy568F) located in similar rocks a few miles to the southeast. Buchia is believed to be the only megafossil present at all four localities, but the species is not known. The only fossils ever collected from the extensive belt of graywacke which crops out along the west coast of Chichagof and Baranof Islands for a distance of nearly 150 miles have been from the west side of Slocum Arm. Field notebook reference: Pomeroy, 1961, Chichagof and Baranof Isalnd, v. 2, p. 100-103. (Attached Sitka B-6 quad. showing localities).
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61APy567F
(Mesozoic loc. M1255)
, Sitka
, Chichagof Island, Slocum Arm. Coords. 6.35, 3.2 Lat. 57 deg. 27.24' N; Long. 135 deg. 49.70' W. Calcareous, fine-grained graywacke. At this locality beds stike nearly E-W and dip steeply (70 deg.) to the south. They are believed to be overturned. Adjacent rocks where exposed along shoreline are nonfossiliferous fine-grained graywacke. Fossil-bearing beds are grayish-green on weathered surface, bluish-gray on fresh surface (description from Pomeroy's transmittal sheet and Jones E&R)
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61APy568F
(Mesozoic loc. M1256)
, Sitka
, Chichagof Island, Slocum Arm. Coords. 6.25, 3.05; Lat: 57 deg. 27.36' N; Long. 135 deg. 49.93' W. Fossils in lithologically similar rocks (note by R.B. Blodgett: referring to above station: 61AFy568F). Fossils themselves are neither as numerous nor as well preserved as at preceding locality. (description from Pomeroy's transmittal sheet and Jones E&R)
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61APy575F
(Mesozoic loc. M1257)
, Sitka
, Chichagof Island, Slocum Arm. Coords. 4.35, 1.7; Lat. 57 deg. 28.57' N; Long. 135 deg. 52.92' W. Locality believed equivalent to Overbeck's station no. 17AOF8 (Museum No. 10148). Fossils in a 20-foot-thick bed of calcareous graywacke. Bed is "coquina-like" and is made of practically total shell material. This fossil horizon is probably lenticular and lies between right-side nonfossiliferous fine-grained graywacke beds. (description from Pomeroy's transmittal sheet and Jones E&R)
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61APy584F
(Mesozoic loc. M1258)
, Sitka
, Chichagof Island, Slocum Arm. Coords. 2.8, 0.1; Lat. 57 deg. 29.90' N; Long. 135 deg. 55.48' W. Locality corresponds to Overbeck's No. 17AOF7 (Museum No. 10147). Fossils in a poorly exposed outcrop of slaty calcareous graywacke. (description from Pomeroy's transmittal sheet and Jones E&R)
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25 of G.C. Martin, 1914
(Mesozoic loc. 8850)
, Sitka
, Admiralty Island, point at north entrance to Herring Bay. Gray shale which appears to underlie the Triassic limestone of Nos. 22, 23, and 24, but which is probably separated from the Triassic limestone by a fault. (description from G.C. Martin, USGS Bull. 776, p. 378)
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Buchia cf. B. crassicollis?
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26 of G.C. Martin, 1914
(Mesozoic loc. 8851)
, Sitka
, Admiralty Island, point between arms of Pybus Bay. G.C. Martin, 1914. (description from G.C. Martin, USGS Bull. 776, p. 378); USGS Mesozoic Iocs. 3271, 3309, 8851, 10095, 10169, 27068, 27071-73, 27334, and 27335 from Pybus Bay area in southeastern part of Admiralty Island, southeast Alaska (Loney, 1964, p. 97). Buchia rugosa (Fischer). (description from Imlay and Detterman, 1973, p. 26); [USGS Mes. Cat.: 8851. Orig. No. 26. Probably Lower Cretaceous. Point between arms of Pybus Bay. Admiralty Island. Alaska. Colls. G.C. Martin and Overbeck. July 4, 1914. Notebook, p. 10.]
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31 of G.C. Martin, 1914
(Mesozoic loc. 8854)
, Sumdum
, Admiralty Island, three-fourths mile northeast of Point Pybus, Conglomerate that appears to underlie shale that yielded lot 30. G.C. Martin, 1914. (description from G.C. Martin, USGS Bull. 776, p. 379)
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32 of G.C. Martin, 1914
(Mesozoic loc. 8855)
, Sumdum
, Admiralty Island, point at west entrance to cove 2 miles northeast of Point Pybus. Concretion in same shale formation that yielded lot. 30. G.C. Martin. (description from G.C. Martin, USGS Bull. 776, p. 379)
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Buchia cf. B. crassicollis?
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17AOF7
(Mesozoic loc. 10147)
, Sitka
, First prominent bight on southwest side of Slocum Arm, 3 miles southwest of Falcon Arm. (description from G.C. Martin, USGS Bull. 776, p. 261) [Jones, 1961 E&R report gives following description: Chichagof Island, Slocum Arm, SW side, three miles SW of entrance to Falcon Arm, first prominent bight on SW side. Collector: R.M. Overbeck, 1917]
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17AOF8
(Mesozoic loc. 10148)
, Sitka
, Second prominent bight on southwest side of Slocum Arm, 5 miles southwest of Falcon Arm. (description from G.C. Martin, USGS Bull. 776, p. 261) [Jones, 1961 E&R report provides following description: Chichagof Island, Slocum Arm. SW side, five miles SW of entrance to Falcon Arm, 2nd prominent bight on SW side. Collector: R.M. Overbeck, 1917.]
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No Data
(Mesozoic loc. 17845)
, Sitka
, N. shore of Mud Bay, Krestof Island [Note by R.B. Blodgett: the only Mud Bay on this 1:63360 quad. sheet is immediately to the west on Kruzof Island!], Baranof Island district. [SW1/4NE1/4, 566] (description from Jones, 1961 E&R report)
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57AL114a
(Mesozoic loc. 27331)
, Sumdum
, Admiralty Island, Sumdum B-6, 2.00, 5.32 graywacke siltstone section overlying Cretaceous(?) conglomerate at Pt. Pybus. a,b,c, collected within 300' stretch of beach, size Aucella increases westward along beach from a to c, a is below b and c, c is top. (description from transmittal sheet of E.H. Lathram dated 10/17/57) [Admiralty Island, Sumdum (B-6 quad., coordinates 2.00, 5.32. From graywacke siltstone overlying Cretaceous? conglomerate at Pt. Pybus. (description from Imlay E&R report of 4/14/59)][Admiralty Island, Sumdum B-6 quad. Coords. 2.00, 5.32. Collector: E. Lathram. (description from Jones, 1961 E&R report)]
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57AL114b
(Mesozoic loc. 27332)
, Sumdum
, Admiralty Island, Sumdum B-6, 2.00, 5.32 graywacke siltstone section overlying Cretaceous(?) conglomerate at Pt. Pybus. a,b,c, collected within 300' stretch of beach, size Aucella increases westward along beach from a to c, a is below b and c, c is top. (description from transmittal sheet of E.H. Lathram dated 10/17/57) [Admiralty Island, Sumdum (B-6 quad., coordinates 2.00, 5.32. From graywacke siltstone overlying Cretaceous? conglomerate at Pt. Pybus. (description from Imlay E&R report of 4/14/59)][ [Admiralty Island, Sumdum B-6 quad. Coords. 2.00, 5.32. Collector: E. Lathram. (description from Jones, 1961 E&R report)]
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57AL114c
(Mesozoic loc. 27333)
, Sumdum
, Admiralty Island, Sumdum B-6, 2.00, 5.32 graywacke siltstone section overlying Cretaceous(?) conglomerate at Pt. Pybus. a,b,c, collected within 300' stretch of beach, size Aucella increases westward along beach from a to c, a is below b and c, c is top. (description from transmittal sheet of E.H. Lathram dated 10/17/57) [Admiralty Island, Sumdum (B-6 quad., coordinates 2.00, 5.32. From graywacke siltstone overlying Cretaceous? conglomerate at Pt. Pybus. (description from Imlay E&R report of 4/14/59)] [Admiralty Island, Sumdum B-6 quad. Coords. 2.00, 5.32. Collector: E. Lathram. (description from Jones, 1961 E&R report)]
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Buchia sp. indeter. Large flattened form.
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