Report on Referred Fossils |
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| Stratigraphic range: |
Lower Jurassic |
| Kinds of fossils: |
Mollusks |
| Quadrangle or area: |
McCarthy C-7 quad. |
| Shipment No.: |
A-71-20 |
| Referred by: |
MacKevett, E. M., Jr.
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| Report prepared by: |
Imlay, Ralph W.
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| Date: |
11/09/1971 |
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The ammonites from the upper member of the McCarthy Formation in the southern part of the McCarthy (C-7) quadrangle are all of Early Jurassic (Sinemurian) age. They represent the same genera as found previously in that member farther east in the Wrangell Mountains. The localities and fossils may be listed as follows:
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Brief statement of problem and remarks (from collector):
Under separate cover I'm sending you five collections of fossils from the McCarthy C-7 quadrangle, Alaska. The collections consists of 71AMk-31E and 36B, and 71AFd-263B, -264, and -267. Their localities are shown on the enclosed map. The fossils are from the upper member of the McCarthy Formation and appear to be similar to fauna collected farther east in the Wrangells that were indicative of the Sinemurian. I will be interested in any identifications and age assignments that you deduce.
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71AMk31E
(Mesozoic loc. 30137)
, Mc Carthy
, None given in E&R report. [Imlay, 1981, USGS Prof. Paper 1148, p. 25 provides the following locality description: E.M. MacKevett, Jr. Center of N1/2SW1/4 sec. 8, T. 4 S., R. 11 E., McCarthy (C-7) quadrangle, Wrangell Mountains, southern Alaska. Lower part of upper member of McCarthy Formation. Early Sinemurian.]; [ USGS Mesozoic loc. 30137. Near center of north half of SW1/4 sec. 8, T. 4 S., R. 11 E., in south-central part of McCarthy (C-7) quadrangle. Mesozoic Iocs. 30138-30140 in west half of sec. 17, T. 4 S., R. 12 E., near southeast corner of McCarthy (C-7) quadrangle. Wrangell Mountains, eastern Alaska. All localities are in upper member of McCarthy Formation. Arnioceras (loc. 30140), Megarietites?, and Arnioceras? (loc. 30139), and arietitid ammonites (locs. 30137 and 30138). (description from Imlay and Detterman, 1973, p. 22); [USGS Mes. Cat.: (71AMK-31E) Jurassic, Upper Member of McCarthy Fm. Center of N1/2 of SW1/4 sec. 8, T. 4 S., R. 11 E., McCarthy C-7 quad., Wrangell Mtns, eastern Alaska. Coll. by E.M. MacKevett, 1971]
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71AMk36B
(Mesozoic loc. 30138)
, Mc Carthy
, None given in E&R report. [Imlay, 1981, USGS Prof. Paper 1148, p. 25 provides the following locality description: E.M. MacKevett, Jr., 1971. SW1/4NE1/4SW1/4 sec. 17, T. 4 S., R. 12 E., McCarthy (C-7) quadrangle, Wrangell Mountains, southern Alaska. Low in upper member of McCarthy Formation. Early Sinemurian.]; Mesozoic locs. 30138-30140 in west half of sec. 17, T. 4 S., R. 12 E., near southeast corner of McCarthy (C-7) quadrangle. Wrangell Mountains, eastern Alaska. All localities are in upper member of McCarthy Formation. Arnioceras (loc. 30140), Megarietites?, and Arnioceras? (loc. 30139), and arietitid ammonites (locs. 30137 and 30138). (description from Imlay and Detterman, 1973, p. 22); [USGS Mes. Cat.: (71AMK-36B) Jurassic, Upper Member of McCarthy Fm. SW1/4 NE 1/4 SW1/4 sec. 17, T. 4 S., R. 12 E., McCarthy C-7 quad., Wrangell Mtns., eastern Alaska. Coll. by E.M. MacKevett, 1971]
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71AFd263B
(Mesozoic loc. 30139)
, Mc Carthy
, None given in E&R report. [Imlay, 1981, USGS Prof. Paper 1148, p. 25 provides the following locality description: A.B. Ford, 1971. On ridge in south-central part of SE1/4NW1/4 sec. 17, T. 4 S., R. 12 E., McCarthy (C-7) quadrangle. Wrangell Mountains, southern Alaska. Low in upper member of McCarthy Formation. Late Sinemurian.]; Mesozoic locs. 30138-30140 in west half of sec. 17, T. 4 S., R. 12 E., near southeast corner of McCarthy (C-7) quadrangle. Wrangell Mountains, eastern Alaska. All localities are in upper member of McCarthy Formation. ..... Megarietites?, and Arnioceras? (loc. 30139), ..... . (description from Imlay and Detterman, 1973, p. 22); Imlay, R.W., and Detterman, R.L., 1973, Jurassic Paleobiogeography of Alaska: U.S. Geological Survey Professional Paper 801, 34 p. [USGS Mes. Cat.: Lower Jurassic, upper member of McCarthy Fm. On ridge in SW1/4 SE1/4 NW1/4 sec. 17, T. 4 S., R. 12 E., McCarthy C-7 quad., Wrangell Mtns., eastern Alaska, coll. by Ford, 1971]
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71AFd264
(Mesozoic loc. 30140)
, Mc Carthy
, None given in E&R report. [Imlay, 1981, USGS Prof. Paper 1148, p. 25 provides the following locality description: A.B. Ford, 1971. On ridge in SW. cor. sec. 17, near sec. 18, T. 4 S., R. 12 E., McCarthy (C-7) quadrangle, Wrangell Mountains, southern Alaska. Early Sinemurian.]; [Mesozoic locs. 30138-30140 in west half of sec. 17, T. 4 S., R. 12 E., near southeast corner of McCarthy (C-7) quadrangle. Wrangell Mountains, eastern Alaska. All localities are in upper member of McCarthy Formation. Arnioceras (loc. 30140), .... (description from Imlay and Detterman, 1973, p. 22)]; [USGS Mes. Cat.: (71AFd264). Lower Jurassic, upper member of McCarthy Fm. On ridge in SW corner sec. 17, near sec. 18, T. 4 S., R. 12 E., McCarthy C-7 quad., Wrangell Mtns, eastern Alaska. Coll. by Ford, 1971]
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