Sample Detail of
Sample: Sample No. 92AD45B -- USGS No. USGS loc. 11950-SD, also 12464-SD
Locality: Field No. 92AD45B
Description: Both samples (92AD45B, 45C) collected along N-S segment of ridge. From a dolomitic brachiopod packstone. (description from Blodgett E&R report of 5/3/94) [Howard Pass B-5. Lat. 68o 29'57" N., Long. 158o 35'35" W. Dolomitic brachiopod packstone. Thin section is dolomite crystal mosaic containing a few silicified bioclasts, including probable brachiopod fragments and crinoid ossicles. Collected from unnamed Devonian limestone, stratigraphically equivalent to 92AD45C but in different facies. These rocks stratigraphically underlie strata at loc. 74; approx. 130 m of total section exposed at the two localities. Heavy-mineral concentrate is chiefly phosphatic brachiopod fragments. Brachiopods of early Eifelian age collected from this locality (see table 3). (description from Dover et al., 2004, p. 43 (Table 1))]; [92AD45B. USGS loc. 12464-SD. Howard Pass B-5. 68°29'58", 158°35'32". Dolomitic brachiopod packstone. Collected from unnamed Devonian limestone, stratigraphically equivalent(?) to 92AD44D and 45C, but in different(?) facies.
Collected north of 92AD44D. (description from Harris E&R reports dated Jan. 25, 1995 (Shipment no. A-95-3a) and March 17, 1995 (Shipment no. A-95-3)]
Location: Alaska Quadrangle: Howard Pass B-5
Township&Range: T11S R29W Section: SE1/4, SW1/4, sec. 12
Lat.: 68o29'57 " Long.: 158o35'35 "
Reference
Title: Report on Referred Fossils ,  1994 (05/03)
Report by: Robert B. Blodgett
Referred by: Julie A. Dumoulin
Age: Eifelian (early Eifelian)
Formation: Unknown (Unknown (unnamed Devonian limestone))
Comment:The most abundant species in all three collections of silicified brachiopods is Spinatrypa (Isospinatrypa) sp., which is conspecific with an undescribed species from the upper part of the Cheeneetnuk Limestone of west-central Alaska. The age of that part of the Cheeneetnuk is early Eifelian (early Early Middle Devonian). The material represented by Schizophoria sp. is too poorly preserved to make a species-level comparison. .... More material of either of the two rhynchonellids (Cassidirostrum? and Cupularostrum?) would be desired, so that interiors could be obtained, which would allow confirmation of generic identications. I would suggest an early Eifelian age for your collections, based on the mutual presence of Spinatrypa (Isospinatrypa) sp., with those of equivalent age faunas from the upper part of the Cheeneetnuk Limestone. As you are aware, Bill Brosge made extensive collections of your stratigraphic interval back in 1950 (localities 50ABe51, 52, and 53). In his collections I was able to also recognize a number of species in common with the Cheeneetnuk faunas of west-central and southwestern Alaska (from rocks of the so-called "Nixon Fork terrane"). This includes the rhynchonellid brachiopod Droharhynchia rzhonsnitskayae Baxter & Blodgett, 1994 (a nomen nudum, until legally published this Nov., 1994). This species also turns up in one of the Brosge samples, 50ABe53 (=UGS loc. 3370-SD). It is indeed intriguing to see suggestions of further alliance between Eifelian age faunas of northwestern and southwestern Alaska!
Occurrence(s)
No. Group Name Qty Notes
1 Brachiopods Schizophoria sp.
2 Brachiopods Cassidirostrum? sp.
3 Brachiopods Cupularostrum? sp.
4 Brachiopods Spinatrypa (Isospinatrypa) sp.
5 Crinoids crinoid ossicles

Title: Geologic and fossil locality maps of the west-central part of the Howard Pass Quadangle and part of the adjacent Misheguk Mountains Quadrangle, western Brooks Range, Alaska ,  2004
Report by: Jim Dover , Irv L. Tailleur , Julie A. Dumoulin
Age: Eifelian-Givetian (Eifelian - early Givetian (early to middle Middle Devonian))
Formation: Unnamed (Unnamed limestone (Devonian))
CAI:Min: 3
Comment:Age: early to middle Middle Devonian; Po. costatus costatus Zone through Lower Po. varcus Subzone; Eifelian, but not very earliest, through early Givetian. According to R. Blodgett (table 3) brachiopods from this locality suggest and early Eifelian age.

Biofacies: Belodellid-polygnathid biofacies, probably polygnathid biofacies as belodellids were probably surface swimmers. Because belodellids are abundant and the Pa elements of the Po. parawebbi still have their basal plate attached, the environmnet of deposition was probably below or near wave base in a shelf depositional setting.

Shown as locality 73 on Sheet 2; Map unit: Dl

CAI=3

Occurrence(s)
No. Group Name Qty Notes
1 Conodonts 140 Belodella devonica (Stauffer) elements All conodonts identified by A.G. Harris
2 Conodonts Polygnathus parawebbi Chatterton, 38 Pa, 16 Pb, 7 M, 6 Sa, 4 Sb, and 6 Sc elements (all Pa elements have their basal plate still attached)
3 Conodonts 46 indet. bar, blade, and platform fragments
4 Vertebrates 6 ichthyoliths

Title: Geologic and Fossil Locality Maps of the West-Central Part of the Howard Pass Quadrangle and Part of the Adjacent Misheguk Mountain Quadrangle, Western Brooks Range, Alaska (part 2 of single issue)) ,  2004
Report by: Jim Dover , Irv L. Tailleur , Julie A. Dumoulin
Age: Eifelian (Early Middle Devonian (early Eifelian))
Formation: Unnamed (Limestone (Devonian))
Comment:Age: early Middle Devonian (early Eifelian)

Shown as locality 73 on Sheet 2; map unit: Dl

Table 1 contains conodont data from this locality.

[all data given here from Dover et al., 2004, p. 65 (Table 3)]

Occurrence(s)
No. Group Name Qty Notes
1 Brachiopods Schizophoria sp. Brachiopods identified by R.B. Blodgett, USGS
2 Brachiopods Cassidirostrum? sp.
3 Brachiopods Cupularostrum? sp.
4 Brachiopods Spinatrypa (Isospinatrypa) sp. Spinatyrpa (Isospinatrypa) sp. is conspecific with an undescribed species from the upper part of the Cheeneentnuk Limestone of west-central Alaska

Title: Report on Referred Fossils ,  1995 (03/17)
Analysis of all samples is given in the accompanying 16-page table. The range of biostratigraphically important samples is shown on the accompanying diagram. The heavy-mineral concentrates were analyzed by Nancy Stamm; the residues have been returned to Julie Dumoulin. Please note a few (~4 samples have heavy-mineral concentrates that include chalcopyrite and bornite).
Report by: Anita G. Harris
Referred by: Julie A. Dumoulin , J. H. Dover
Age: Eifelian-Givetian (Eifelian, but not very earliest - early Givetian)
Formation: Unnamed (Unnamed Devonian limestone)
CAI:Min: 3
Comment:Age: Po. costatus costatus Zone through Lower Po. varcus Subzone; Eifelian, but not very earliest, through early Givetina; = early to middle Middle Devonian). According to R. Blodgett (report to J.A. Dumoulin) the brachiopods suggest an early Eifelian age.
Biofacies: Belodellid-polygnathid biofacies, probably polygnathid biofacies as belodellids were probably surface swimmers. Because belodellids are abundant and the Pa elements of the Po. parawebbi still have their basal plate attached, the environment of deposition was probably below or near wave base in a shelf depositional setting.
CAI = 3.

Heavy-mineral concentrate: chiefly phosphatic brachiopod fragments, dolomite rhombs and lesser clusters of weather pyrite euhedra.
The +20 mesh acid insoluble residue given to R. Blodgett for brachiopod analysis.

Note that two separate USGS fossil locality numbers exist for this collection: 11950-SD (for the brachiopods) and 12464-SD (for the conodonts).

Occurrence(s)
No. Group Name Qty Notes
1 Conodonts 140 Belodella devonica (Stauffer) elements
2 Conodonts Polygnathus parawebbi Chatterton 38 Pa, 16 Pb, 7 M, 6 Sa, 4 Sb and 6 Sc elements - all Pa elements have their basal plate still attached
3 Conodonts 46 indet. bar, blade, and platform fragments
4 Vertebrates 6 ichthyoliths

Title: Report on Referred Fossils ,  1995 (01/25)
All conodont analyses and samples and residue weights are given in the attached tables. The age range of all samples is graphically shown on the accompanying diagram.

Please give a copy of this report to Jim Dover and anyone else on the Howard Pass project that needs these data. I will do all the Carboniferous samples while in Florida.
Report by: Anita G. Harris
Referred by: Julie A. Dumoulin
Age: Eifelian-Givetian (Eifelian (but not very earliest) - early Givetian)
Formation: Unnamed (unnamed Devonian limestone)
CAI:Min: 3
Comment:Age: Po. costatus costatus Zone through Lower Po. varcus Subzone; Eifelian, but not very earliest, through early Givetian; = early to middle Middle Devonian). According to R. Blodgett (report to J.A. Dumoulin) the brachiopods suggest an early Eifelian age.
BIOFACIES: Belodellid-polygnathid biofacies, probably polygnathid biofacies as belodellids were probably surface swimmers. Because belodellids are abundant and the Pa elements of the Po. parawebbi still have their basal plate attached, the environment of deposition was probably below or near wave base in a shelf depositional setting.
CAI = 3

Heavy mineral concentrate: chiefly phosphatic brachiopod fragments, dolomite rhombs and lesser clusters of weathered pyrite euhedra. The +20 mesh acid insoluble residue was given to R. Blodgett for brachiopod analysis.
Wgt. (kg) 11.0; >20 mesh insol. res., (grams) ~ 1500; 20-200 mesh insol. res., (grams) 164

Occurrence(s)
No. Group Name Qty Notes
1 Conodonts 140 Belodella devonica (Stauffer) elements
2 Conodonts Polygnathus parawebbi Chatterton 38 Pa, 16 Pb, 7 M, 6 Sa, 4 Sb and 6 Sc elements all Pa elements have their basal plate still attached
3 Conodonts 46 indet. bar, blade, and platform fragments
4 Vertebrates 6 ichthyoliths