Reference Detail of

Report on Referred Fossils
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Stratigraphic range: Devonian - Mississippian
Kinds of fossils: Marine invertebrates
Quadrangle or area: Chandalar, Arctic and Philip Smith quads., Northern Alaska
Shipment No.: A-60-24
Referred by: Brosge, William P.
Report prepared by: Dutro, J. Thomas, Jr.
Date: 12/11/1961

This report covers 34 collections containing more than five hundred specimens, mostly of Devonian age. Two collections are from the Lisburne group, three from the Kayak shale (?) and one contains a mixture of Lisburne and Kayak rocks and fossils.

The corals have been reported on separately by W. A. Oliver, Jr. (see report of 2/16/61) and his identifications are included in the lists below for completeness.

Kayak Shale (?)
In addition to the two collections transmitted from this formation, one collection 60Abe 762 contains a Kayak-like fossil assemblage. Another, 60ARr 796 has a mixture of rock types and fossils that suggests both Lisburne and Kayak sources.

Summary
The preponderance of faunal information on the Devonian slate-sandstone unit points to an early Late Devonian (Frasnian) age. Two collections (Be 620, Be 547) are possibly younger (Famennian), so close to the top of this formation, suggests that in some places the whole unit may be Frasnian. In general, the presence of Cyrtospirifer and Atrypa together in a collection indicates a late Frasnian age (as in Rr 784). In addition, Cyrtospirifer is unknown below the upper Devonian.

The Devonian limestone-siltstone unit is dated as Frasnian by collection Rr 426. The coral association including Macgeea, along with Atrypa in this case, is definitive.

The age of the Skajit limestone is enigmatic. Several collections suggest an early Late Devonian age for a part of this formation, but only Rr 787 is definitely assigned that age, on the basis of its coral assemblage. This collection also includes the large pelecypod Pycinodesma? sp. One collection is most likely Middle Devonian because of the identification of Stringocephalus? sp. The formation could well range from Middle to early Late Devonian age (as, for example, does the Devil’s Gate of Nevada). Although many of the collections can not be pinned down precisely as to age, all would be consistent with this interpretation.


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Brief statement of problem and remarks (from collector):
Are the black shales of Be580 and Rr697 & 712 Mississippian or Devonian?

Is Be549A correlative with the Devonian graywacke or with the Devonian limestone-siltstone?

Does Be557 (like Be555D) correlate with Skajit, Dev. ls.-silt.? or Lisburne??

Are any of the thin limestones in the Devonian slate-sandstone correlative with the Skajit or the Dev. ls.-silt.?
User Note module to be added
60ARr 420 , Philip Smith Mts , Black limestone 100 to 200 feet thick in shale (750 to 1000 ft. below base of Kanayut). Possible Skajit?.
Cylindrophyllum sp.
Cladopora sp. or
Thamnopora sp.
brachiopod, indet.
60ABe 549A , Arctic , Calcareous shale below graywacke and at high angle fault contact with Skajit. Devonian slate-sandstone unit.
Spinatrypa? sp.
60ABk 202 , Arctic , Brown weathering ls. lenses in slate and siltstone. Devonian slate-sandstone unit.
crinoid columnals, indet.
Macgeea sp.
Alveolites sp.
Schizophoria sp. (large)
60ABe 390 , Philip Smith Mts , Twenty foot limestone in shale. Eighty feet below base of Kanayut. Devonian slate-sandstone unit.
Phillipsastraea sp.
Cladopora sp.
Thamnopora sp.
60ARr 449 , Philip Smith Mts , Dark, fine-grained fetid, limestone beneath shale. Possible Skajit?
Thamnopora sp.
Alveolites sp.
Cyrtospirifer? sp.
60ABe 386C , Chandalar , Black Ls. in upper 100 ft. of Devonian limestone-siltstone unit.
Amphipora? sp.
crinoid columnals, indet.
60ARr 426 , Chandalar , Red weathering limestone infolded with conglomerate, Devonian limestone-siltstone.
Macgeea sp.
Alveolites sp.
Aulopora sp.
Cladopora sp.
Atrypa? sp.
gastropods, indet.
60ARr 397 , Chandalar , Ls. dark gray to gray black, fine to coarse-grained.
Thamnophyllum? sp.
Alveolites sp.
Thamnopora sp.
Amphipora sp.
moderately low-spired gastropd, indet.
60ARr 672 , Christian , Probably from station Rr 673. Skajit ls.
Disphyllum sp.
phacelloid rugose corals, undet.
stromatoporoids, indet.
60ARr 785 , Arctic , Limestone at contact with basal conglom. of Devonian slate - s.s.; Skajit ls.
Hexagonaria sp.
Thamnopora sp.
60ARr 787 , Arctic , Massive ls. rubble; Skajit ls.
Macgeea sp. or
Thamnophyllum sp.
Thamnopora sp.
Amphipora sp.
Pycinodesma? sp.
high-spired gastropod, indet.
60ABe 389 , Chandalar , River cobble probably Skajit.
rugose corals, undet.
Favosites? sp.
60ABe 411 , Chandalar , Local cobbles in mountain canyon in Skajit ls.
Cladopora? sp.
60ABe 557 , Arctic , Black ls. overlain by pink silty ls. and phyllite like 60ABe 555D of Sept. 27 shipment. Skajit ls.
Disphyllum sp.
Thamnopora sp.
60ABk 203 , Arctic , Massive gray to black ls.; Skajit ls.
Disphyllum? sp.
Thamnopora sp.
Amphipora sp.
60ARr 797 , Philip Smith Mts , Limestone, blackcherty, crinoidal.
Spirifer cf. S. logani Hall
60ABe 748 , Arctic , Limestone, light gray, med. to coarse grained, crinoidal, 60% light gray chert & silicified ls.
large crinoid stems, including Platycrinus columnals
zaphrentoid corals, undet.
Spirifer sp. (perhaps cf. S. gregeri Weller)
60ARr 697 , Arctic , Blackslate and red weathering thin-bedded ls.
fenestrate bryozoans, indet.
horn coral, indet. (mold)
60ARr 712 , Arctic , Blackslate, brown weathering mudstone and thin ls.
crinoid columnals, indet.
Chonetes sp. (small)
Spirifer sp. (small)
rhynchonelloid brachiopod, indet.
Syringothyris? sp.
60ABe 762 , Arctic , Brown slate, micaceous siltslate & very fine s.s.
crinoid columnals, indet.
fenestrate bryozoans, indet.
Schuchertella? sp.
Spirifer sp. (small)
60ARr 796 , Philip Smith Mts , Graywacke and siltstone close to fault contact with Lisburne. Fossils from rubble.
Schuchertella? sp.
Productella? sp.
punctate spiriferoid, indet.
pelecypod molds and casts, indet.
orthocone cephalopod, indet.
crinoid columnals, indet.
60ABe 620 , Arctic , Dark brown, manganese stained quartzite. Devonian slate-sandstone.
Cyrtospirifer spp.
camarotoechid brachiopod, indet.
Leiorhynchus sp.
60ABe 547 , Arctic , Calcareous s.s. & sandy ls. in graywacke & quartzite. Devonian slate-sandstone.
Cyrtospirifer spp.
small pelecypod molds and casts, indet.
60ARr 784 , Arctic , Graywacke. Devonian slate-sandstone unit.
Atrypa sp. (large)
Cyrtospirifer? sp.
60ABk 201 , Arctic , Silty ls. in green siltstone. Devonian slate-sandstone unit.
crinoid columnals, indet.
bivalve shells, indet. (small, squeezed molds and casts)
60ARr 618 , Arctic , Slate and limonitic siltstone. Devonian slate-sandstone unit.
Schizophoria sp.
productellid brachiopod, indet.
Cyrtospirifer sp.
pectenoid clams, undet.
Euphemites sp.
low-spired anomphalid gastropod, indet. (cf. Isonema)
60ABe 580 , Arctic , Black micaceous silty shale and shaly brown ls. Fault contact with Lisburne. Devonian slate-sandstone unit.
pelecypods, indet. (molds and casts)
gastropod steinkerns, indet.
60ABe 391 , Philip Smith Mts , Same horizon as Be 390.
60ARr 442 , Philip Smith Mts , White weathering calcareous slate in black slate. Devonian slate-sandstone unit.
small gastropod steinkerns, indet.
60ARr 786 , Arctic , Siltstone, partly calcaresou, partly conglomeratic. At contact with Skajit. (Fossils possibly from Skajit). Devonian limestone-siltstone unit.
low-spired anomphalid, indet. (cf. Isonema)
60ARr 782 , Arctic , Silicified ls.
favositoid coral, indet.
cf. Mourlonia sp.
"Bembexia"? sp.
Straparollus (Euomphalus?) sp.
moderately high-spired gastropod, undet.
subulitid gastropods, indet.
small gastropods (several kinds, probably young stages of those listed above)
60ARr 798 , Philip Smith Mts
Favosites sp.
Thamnopora sp.
Pycinodesma? sp.
60ABe 363 , Chandalar , Black fine grained, medium to thin bedded ls. underlies 300 ft. of calcareous silt and silty ls.
moderately low-spired gastropod, indet. (possibly Euconospira)
60ABe 412 , Chandalar , Local cobbles in mountain canyon in Skajit ls.
Stringocephalus? sp.