Sample Detail of
Sample: Sample No. 67AWK112 -- USGS No. Mesozoic loc. 29870
Locality: Field No. 67AWK112
Description: from upper member of McCarthy Fm. in the McCarthy B-4 quadrangle (description from Imlay E&R report, 10/16/68) [E.M. MacKevett, Jr., 1967. On north side of Chitistone Mountain in east-central part of NE1/4NW1/4 sec. 27, T. 4 S., R. 16 E., McCarthy (B-4) quadrangle. Wrangell Mountains, southern Alaska. Upper member(?), McCarthy Formation, Hettangian. (from Imlay, 1981, p. 25)]; [Many localities in upper member of McCarthy Formation, in McCarthy C-4, C-5, and B-4, quadrangles, Wrangell Mountains, eastern Alaska (MacKevett, 1970a, b, 1971). Ammonites include Arietites (loc. 29870), Arnioceras (Iocs. 28535, 28536, 28538, 28688), Crucilobiceras (loc. 28537, 28540, 28671-73), and Microderoceras (loc. 14472). (description from Imlay and Detterman, 1973, p. 22)]; [USGS Mes. Cat.: Lower Jurassic. Orig. No. 67 AWK 112. Upper Member, East-central part NW 1/4/ NW1/4 sec. 27, T. 4 S., R. 16 E., McCarthy Bo-4 quad., on north side of Chitistone Mtns. Collector: Ed. M. Mackevett, 1967]; [Many localities in upper member of McCarthy Formation, in McCarthy C-4, C-5, and B-4, quadrangles, Wrangell Mountains, eastern Alaska (MacKevett, 1970a, b, 1971). Ammonites include Arietites (loc. 29870), Arnioceras (Iocs. 28535, 28536, 28538, 28688), Crucilobiceras (loc. 28537, 28540, 28671-73), and Microderoceras (loc. 14472). (description from Imlay and Detterman, 1973, p. 22)];[USGS Mes. Cat.: Lower Jurassic. Orig. No. 67 AWK 112. Upper Member, East-central part NW 1/4/ NW1/4 sec. 27, T. 4 S., R. 16 E., McCarthy B-4 quad., on north side of Chitistone Mtns. Collector: Ed. M. Mackevett, 1967]
Location: Alaska Quadrangle: Mc Carthy B-4
Township&Range: T4S R16E Section: east-central part of NE1/4NW1/4 sec. 27
Reference
Title: Report on Referred Fossils ,  1968 (10/16)
Report by: Ralph W. Imlay
Referred by: E. M. MacKevett , Jr.
Age: Sinemurian (early Sinemurian)
Formation: McCarthy Formation
Comment:Fossil collection 67AWK112 contains the lower Sinemurian ammonite Arietites identical with the species that I described from northern Alaska (Prof. Paper 274-D, p. 10, figs. 7,8). The genus is characterized by subquadrate whorls, but strong nearly radial ribs that bend forward near the venter, and by the venter bearing three keels separated by two furrows. The collection also contain fragments of ammonites suggestive of the subfamily Arietitinae, and some fragmentary pelecypods.
Occurrence(s)
No. Group Name Qty Notes
1 Ammonoids Arietites (identical with sp. described by Imlay in USGS Prof. Pap. 274-D, pl. 10, figs. 7, 8)
2 Ammonoids fragments of ammonites suggestive of the subfamily Arietitinae
3 Bivalves fragmentary pelecypods

Title: Early Jurassic Ammonites from Alaska ,  1981
Report by: Ralph W. Imlay
Age: Hettangian
Formation: McCarthy Formation (Upper member(?) of McCarthy Formation)
Comment:Locality shown on Figure 2.

Faunal list given in Table 4

Occurrence(s)
No. Group Name Qty Notes
1 Ammonoids Arietitid genus undetermined

Title: Jurassic Paleobiogeography of Alaska ,  1973
ABSTRACT: Jurassic marginal seas occupied considerable areas in southern and northern Alaska and in the western part of the Kuskokwim region of southwestern Alaska. They appear to have been absent during late Callovian time, much restricted during Hettangian, Bathonian, early Oxfordian and late Tithonian time, and most extensive during Sinemurian, Bajocian, and late Oxfordian to middle Tithonian time. A large area in central Alaska was probably never covered. A southwestern prolongation of that area from the Talkeetna Mountains westward to the western end of the Alaska Penin- sula was the site of granitic intrusions during late Early Jurassic time and of extensive erosion during Middle and Late Jurassic time. Variations in the rate of uplift of the area of these granitic intrusive rocks may explain why marine transgressions and regressions were at different times in southern than in northern Alaska during the Bajocian and Bathonian. Connection of the northern and southern marginal seas occurred through Yukon Territory and eastern- most Alaska. The Jurassic ammonite succession in Alaska is similar to that in central and northern Europe and northern Asia. In Lower Jurassic beds, it is essentially identical. In Bajocian and in Oxfordian to lower Kimmeridgian beds, the ammonite succession in Alaska differs from that in the other areas mainly by the presence of some genera found only in areas bordering the Pacific Ocean and by the absence of a few genera common in central and northern Europe. In con- trast, the Bathonian rocks of Alaska contain ammonites, such as Arcticoceras, Arctocephalites, and Cranocephalites, that are widespread in the Arctic region but are unknown in central Europe. Comparisons with the Tithonian of Europe are not possible because ammonites of that age, other than Lytoceras and Phylloceras, are not yet known from Alaska. The Alaskan Jurassic ammonites of late Pliensbachian Age and of Bathonian to early Kimmeridgian Age belong mostly to the Boreal realm and have very little in common with Tethyan realm ammonites such as those found in areas bordering the Mediterranean Sea.
Report by: Ralph W. Imlay , Robert L. Detterman
Age: Sinemurian
Formation: McCarthy Formation (McCarthy Formation (upper member))
Comment:Age: Sinemurian

upper member of McCarthy Formation

Generalized location shown as locality 8 in figure 2

Occurrence(s)
No. Group Name Qty Notes
1 Ammonoids Arietites