Sample Detail of
Sample: Sample No. 63ABe47B -- USGS No. Mesozoic loc. 29737
Locality: Field No. 63ABe47B
Description: W.P. Brosge, 1963, Spike Mountain, about 30 miles north of Old Rampart, Porcupine River area, Coleen quad., east-central Alaska. Glenn Shale (in part), thin unit of hematitic conglomeratic sandstone interbedded with black, fine-grained quartzite sandstone. (description from Imlay E&R report, 2/14/77) [W.P. Brosge, 1963. Spike Mountain, about 3 miles (48 km) north of Old Rampart, lat. 63o 35.75' N., long 141o 40' W. [Note by R.B. Blodgett: lat. incorrect as given, should be 67o], Porcupine River area, Coleen quadrangle, east-central Alaska. Glenn Shale (in part). A thin unit of red conglomeratic sandstone interbedded with black, fine-grained quartzitic sandstone. Early Hettangian. (from Imlay, 1981, p. 24)]; [USGS Mesozoic locs. 29737 and 29738. From Spike Mountain near the Porcupine River about 30 miles north of Old Rampart, Coleen quadrangle, lat 63°35.75' N., long 141°40' W. Psiloceras. (description from Imlay and Detterman, 1973, p. 21)]; [[USGS Mes. Cat.: Lower Jurassic. Orig. No. 63ABe47B. From thin unit of hematitic congl. ss. interbedded in black, very fine-grained quartzitic ss. on Spike Mtn., Coleen Quadrangle, Lat. 63°35.75' N., Long 141°40' W., Porcupine River Area, eastern Alaska. Collector: Brosge, 1963]
Location: Alaska Quadrangle: Coleen C-2
Lat.: 67o35.75 ' Long.: 141o40' "
Reference
Title: Early Jurassic Ammonites from Alaska ,  1981
Report by: Ralph W. Imlay
Age: Hettangian (early Hettangian)
Formation: Glenn Shale
Comment:Shown as locality 14 on Figure 1

See Table 3 for faunal list

Occurrence(s)
No. Group Name Qty Notes
1 Ammonoids Psiloceras sp.
2 Ammonoids Psiloceras (Franziceras) cf. P. (F.) ruidum (Buckman)

Title: Report on Referred Fossils ,  1977 (02/14)
The fossils from the Old Rampart area examined previously in 1975 (see report A-75-1) have been restudied for inclusion in a Professional Paper and are listed as follows:
Franziceras cf. rudidium (Buckman) at U.S. Geol. Survey Mesozoic locs. 29737, 29739, 29742. [Note by R.B. Blodgett: species name misspelled in E&R report, should be ruidum]
F. sp. at Mesozoic loc. 29742
F.? sp. at Mesozoic locs. 29740 and 29737.
Psiloceras sp. at Mesozoic loc. 29737.
Amaltheus stokesi (J. Sowerby) at Mesozoic loc. 29340.
Franziceras and Psiloceras occur nearly worldwide in the basal Hettangian at the base of the Jurassic. Amaltheus occurs in the upper Pliensbachian of northwestern Europe and as far south as British Columbia in North America.
The localities listed above are described below. Unless you inform me otherwise the fossil identifications, age determinations and locality descriptions are written herein will be used in a publication.
Report by: Ralph W. Imlay
Referred by: Irv L. Tailleur
Age: Hettangian
Formation: Glenn Shale
Occurrence(s)
No. Group Name Qty Notes
1 Ammonoids Franziceras cf. F. ruidum (Buckman) species name misspelled as rudidium in report
2 Ammonoids Franziceras? sp.
3 Ammonoids Psiloceras sp.

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: Hettangian
Formation: Unknown (Unknown (not given))
Comment:Age: Hettangian

Generalized location shown as locality 3 in figure 2

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