Sample Detail of
Sample: Sample No. 69AHr137 -- USGS No. Mesozoic loc. 29874
Locality: Field No. 69AHr137
Description: East bank of Allen River at the middle rapids. Impure, gray, highly fossilifeous limestone, associated with at least one 6'-10' bed of calcareous chert grit conglomerate.; [USGS Mesozoic loc. 29874. East bank of Alien River at middle rapids, Tikchik Lakes area, lat 60°7' N., long 158°38' W., Taylor Mountains A-8 quad- rangle. Kuskokwim region, southwest Alaska. Weyla and other pelecypods identical with species in basal Jurassic near Seldovia on the Kenai Peninsula (loc. 13). These could be of Hettangian or Sinemurian Age. (description from Imlay and Detterman, 1973, p. 22)]; [USGS Mes. Cat.: Basal Jurassic. Orig. No. 69AHR 137. East bank of Allen River at Middle Rapids. Impure gray Ls. associated with one 6' - 10' bed of calc. chert grit or congl. Long. 158° 38' W., Lat. 60° 7' N., Taylor Mtns. A-8 quad., Kuskokwim Region. Alaska. Collector: J.M. Hoare, 1969]
Location: Alaska Quadrangle: Taylor Mts A-8
Lat.: 60o07' " Long.: 158o38' "
Reference
Title: Report on Referred Fossils ,  1970 (11/20)
Report by: Ralph W. Imlay
Referred by: Joseph M. Hoare
Age: Early Jurassic (Lower Jurassic)
Comment:The additional collections from locality 69AHr137 contain several specimens of Weyla, a characteristic Lower Jurassic genus, and one specimen of Oxytoma, which genus ranges from the top of the Triassic into the Upper Cretaceous. With these additions to the fossils previously reported (A-69-20), a Lower Jurassic age is assured.
Occurrence(s)
No. Group Name Qty Notes
1 Bivalves Weyla several
2 Bivalves Oxytoma 1

Title: Report on Referred Fossils ,  1969 (12/17)
Report by: Ralph W. Imlay
Referred by: Joseph M. Hoare
Age: Early Jurassic (Lower Jurassic?)
Comment:Contains fragmentary pelecypods that are tentatively assigned to Cardinia, Entolium, Velata, Aequipecten, Pleuromya, Trigonia. These are definitely Mesozoic, are probably not younger than Jurassic, and do not include any genera that are characteristic of the Triassic. Neither do they include genera that are common throughout most of the Jurassic in Alaska. The pelecypod assemblage, however, closely resembles that found in the basal Jurassic (Hettagnian and Sinemurian) exposed on the Kenai Peninsula between Seldovia and Port Graham at USGS Mesozoic localities 2978, 2981, 6384, 21238, 21241 and 21242. These resemblances suggest that collection 69AHr137 was obtained near the base of the Jurassic. Such a stratigraphic position would explain the absence of any pelecypod genera characteristic of the Triassic, such as Monotis. It would also explain the absence of some pelecypod genera that are characteristic of the Jurassic but that did not appear until late Early or Middle Jurassic time. The brachiopods were examined by Mackenzie Gordon who says that they are post-Paleozoic. The gastropod fragments are poorly preserved and are of little age significance.
Occurrence(s)
No. Group Name Qty Notes
1 Bivalves Cardinia
2 Bivalves Entolium
3 Bivalves Velata
4 Bivalves Aequipecten
5 Bivalves Pleuromya
6 Bivalves Trigonia
7 Brachiopods post-Paleozoic brachiopods
8 Snails poorly preserved gastropods

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-Sinemurian (Hettangian or Sinemurian)
Formation: Unknown (not given)
Comment:Age: Hettangian or Sinemurian <>Generalized location shown as locality 11 in figure 2

Weyla and other pelecypods identical with species in basal Jurassic near Seldovia on the Kenai Peninsula

Occurrence(s)
No. Group Name Qty Notes
1 Bivalves Weyla identical with species in basal Jurassic near Seldovia on the Kenai Peninsula
2 Bivalves other pelecypods identical with species in basal Jurassic near Seldovia on the Kenai Peninsula