Sample Detail of
Sample: Sample No. 4AC15
Locality: Field No. 4AC15
Description: 1 1/2 miles southeast of Wevok (description from Collier, 1906, p. 23) [Martin, 1926, p. 112 gives following description: "1 1/2 miles southwest of Wevok. Chert, cherty limestone, and shale. A.J. Collier, 1904"]
Location: Alaska Quadrangle: Point Hope D-2
Reference
Title: Geology and coal resources of the Cape Lisburne region, Alaska ,  1906
Quote from George H. Girty on p. 22 concerning Carboniferous invertebrate fossils: "The Carboniferous faunas of Alaska are different from those of central and eastern United States, and comprise either new species or ones described in more or less casual papers upon Russian or Asiatic paleontology. The paleontologist, therefore, labors under some difficulty in reporting upon such collections, since it is not only often impossible to give lists with specific determinations, but even faunal comparisons and correlations are attended with uncertainity."
Report by: Arthur J. Collier
Age: Mississippian
Comment:In this same region a series of collections was obtained, representing a fauna not yet collected at Cape Lewis. In this group belong the following lists: southeast of Wevok, 4AC15, 4AC18, 4AC21, 4AC81, 4AW34, and 4AW45. This fauna comprised little besides pectinoid shells, of which four or five species are present. It has been treated rather cursorily, because pectinoids are not good for correlation and age determination, since the number of species described is very great and it is seldom, possible among Paleozoic specimens to be really certain of the true generic position. I may say, however, that the types represented are such as are found in the United States in the Devonian and Lower Carboniferous. As the strata from which the material was obtained, appear to be implicated with the softer beds near Cape Lewis, this horizon can pretty safely be assigned to a place early in the Lower Carboniferous. I may add that it is not uncommon to find bands filled with shells of the Pecten group to the exclusion of almost every other type. In the present case at some points were found in association a small smooth shell and a large vaulted one with radial ribs, similar to Pararca, the generic position of neither of which has been ascertained. (from p. 25)
Occurrence(s)
No. Group Name Qty Notes
1 Sponges Sponge? fossils identified by George H. Girty
2 Bivalves Aviculopecten 2 sp.

Title: Mesozoic Stratigraphy of Alaska ,  1926
Report by: G. C. Martin
Age: Late Triassic
Formation: Unnamed (Shale, chert, and limestone near Cape Lisburne)
Comment:The Upper Triassic rocks near Cape Lisburne were first described by Collier13 as the "middle formation" of the local Carboniferous section, and were assigned to the lower Carboniferous because of their apparent position beneath the Lisburne limestone and above the "lower formation," both of which contain lower Carboniferous fossils.
The same publication includes a short general discussion of the fauna of these beds by G.H. Girty,14 with lists of the fossils that Collier collected. The fossils from the beds that are now regarded as Triassic were discussed briefly, with a statement that they are different from the characteristic lower Carboniferous faunas of other formations and seem to include no diagnostic forms, and were assigned tentatively to the lower Carboniferous on the basis of an assumption that the strata from which they were obtained are interbedded with the known Carboniferous rocks.
The presence of Upper Triassic rocks near Cape Lisburne was first pointed out by Kindle15 on the basis of the following statement by Stanton:

"Among the collections obtained by Mr. Collier in the Cape Lisburne region some years ago there are several small lots consisting mainly of a form that seems identical with Pseudomonotis subcircularis and probably come from about the same horizon as this Cape Thopmson locality. These fossils were at that time identified as Aviculopecten and referred to the Carboniferous, chiefly because of the stratigraphic relations they were supposed to hold with well-characterized Carboniferous faunas."

Kindle added a brief statement indicating which of the collections previously regarded as Carboniferous were to be considered probably Triassic.

The Triassic rocks at Cape Lisburne were described briefly, on the basis of Collier's description, by Martin,16 who pointed out that the entire "middle formation" of Collier is probably Triassic. [from Martin, 1926, pp. 108-109]

The "middle formation" has been recognized in three of four areas in the Lisburne region. The area that yielded most of the Triassic fossils (lots 4AC15, 4AC18, 4AC21, 4AC81, 4AW33, 4AW34) is a belt about 2 miles wide which extends southeastward from a point on the coast near Wevok, about 3 miles east of Cape Lisburne, between and area of supposed Cretaceous rocks on the northeast and an area of the Lisburne limestone on the southwest. The contact of the "middle formation" with the supposed Cretaceous rocks, as indicated in Figure 2, was regarded by Collier as probably an overthrust fault. [Martin, 1926, pp. 109-110]

Age and correlation.--The Triassic shale, chert, and limestone near Cape Lisburne have yielded the fossils listed in the following table. The presence of Pseudomonotis subcircularis indicates a correlation with the Pseudomonotis-bearing beds at the tip of the Upper Triassic. No trace of the older Triassic faunas have been found near Cape Lisburne. [from Martin, 1926, pp. 111-112]

REFERENCES:
13Collier, A.J., Geology and coal resources of the Cape Lisburne region, Alaska: U.S. Geol. Survey Bull. 287, pp. 16, 18, 19-21, pl. 1, 1906.
14Idem, pp. 22-26.
15Kindle, E.M., The section at Cape Thompson, Alaska: Am. Jour. Sci., 4th ser., vol. 28, pp. 527-528, 1909.
16Martin, G.C., Triassic rocks of Alaska: Geol. Soc. America Bull., v. 27, pp. 703-704, 1916.

Occurrence(s)
No. Group Name Qty Notes
1 Sponges Sponge? identified by George H. Girty
2 Bivalves Pseudomonotis subcircularis (Gabb) Identified by T.W. Stanton