Sample Detail of
Sample: Sample No. 49AMr40 -- USGS No. Mesozoic loc. 21770
Locality: Field No. 49AMr40
Description: Tuxedni formation, probably middle siltstone member. Isolated outcrop of siltstone on northwest bank of Fitz Creek, 1.75 miles S. 83o E. of Tonnie Peak, Iniskin Peninsula. (description from Imlay E&R report of 1/16/50)[Grantz transmittal sheet of Nov. 23, 1949 provides following description: "Microfossils from isolated outcrop of siltstone on NW bank of Fitz Creek, 1.75 miles S 83 E of Tonnie Peak. This outcrop is either lower or middle siltstone member of the Tuxedni--identification is critical to the interpretation of the structure. Unfortunately, only pelecypods could be found; can anything be determined from them?"]; [Shown as locality 1 on Pl. 3 of Detterman and Hartsock, 1966]
Location: Alaska Quadrangle: Iliamna D-1
Reference
Title: Report on Referred Fossils ,  1950 (01/16)
Title: Report on Jurassic fossils from west side of Cook Inlet, southwestern Alaska, submitted by John A. Hartsock and Don Miller, December 15, 1949 (AF-49-10) Examination has been made of the collections of Jurassic fossils made in 1949 along the west side of Cook Inlet by Miller, Hartsock, and Grantz. There is no question concerning the age or stratigraphic position of most of the collections but a few require comment.

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None of the other lots present any age problems. I hope to complete describing the Callovian ammonites early this spring and at that time will sent you a summary of conclusions.
Report by: Ralph W. Imlay
Referred by: John K. Hartsock , Don J. Miller , Arthur Grantz
Age: Jurassic (Jurassic, no further definitive age is given in E&R report)
Formation: Tuxedni Group (Tuxedni formation, probably middle siltstone member)
Comment:Lot 49AMr40 (Mes. loc. 21770) contains a species of Inoceramus with swollen umbones, and a fairly smooth Pleuromya. Such Inoceramus are characteristic of the Kialagvik formation at Wide Bay. On the Iniskin Peninsula they are common in the lower siltstone member but also occur in the middle siltstone member. Smooth Pleuromyas are common in the middle siltstone member and uncommon in the lower member in which most of the Pleuromyas are very coarsely ribbed as in the type Kialagvik formation on Wide Bay. The evidence is not positive, but it appears probable that the collection comes from the middle siltstone member.
Occurrence(s)
No. Group Name Qty Notes
1 Bivalves Inoceramus sp.
2 Bivalves Pleuromya sp.
3 Bivalves Grammatodon sp.

Title: Geology of the Iniskin-Tuxedni Region, Alaska ,  1966
Report by: Robert L. Detterman , John K. Hartsock
Age: Bajocian
Formation: Red Glacier Formation
Comment:Geographic location: Tonnie Creek area
Map reference (pl. 3): 1
Stratigraphic position below top of formation (ft): 100-150
all above data from Table 4, p. 24
Occurrence(s)
No. Group Name Qty Notes
1 Bivalves Grammatodon sp. fauna identified by R.W. Imlay
2 Bivalves Inoceramus sp.
3 Bivalves Pleuromya sp.