Hill Annex Mine (Cretaceous of the United States)

Where: Itasca County, Minnesota (47.3° N, 93.3° W: paleocoordinates 46.0° N, 54.8° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Coleraine Formation, Turonian (93.9 - 89.8 Ma)

• "On the basis of the fauna [the fm.] is considered the age equivalent of the lower Benton in the Colorado series." TURONIAN info from R.E. Sloan (1964) The Cret. Syst. in MN; Minn. Geol. Surv. Rept. Invest. 5

• formation-level stratigraphic resolution

Environment/lithology: marine; poorly lithified, green shale and conglomerate

• "In the south face of the mine 24-28 ft of Cret sediments occur. 10-18 ft of coarse basal conglomerate is overlain by 12-20 ft of fossiliferous gritty lean ore. In the upper part of the grit are erosion channels filled with green shales making patches 4-5 ft thick and containing abundant oyster shells but weathered so that the material is mealy. The upper part of the grit is softer than the remainder and occasionally shows fine laminations. There is a fossiliferous green shale in the SE corner of the mine."

Collection methods: surface (in situ), mechanical,

• "During a 12 month period in 1937 and 1938 the writer studied in detail the Mesabi invertebrate fossil collection at the University of Minnesota...Good fossil specimens were difficult to find during the field season of 1937 when the writer visited the region."

Primary reference: H. R. Bergquist. 1944. Cretaceous of the Mesabi Iron Range, Minnesota. Journal of Paleontology 18(1):1-30 [J. Alroy/M. Sommers/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 1987: authorized by John Alroy, entered by Mike Sommers on 15.06.1999, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

• No attempt was made to identify any vertebrate material such as shark and reptile teeth and vertebrae, which are rather plentiful. The plant life has likewise been neglected..."
Crustacea indet. Brünnich 1772
"crustacean fragments"
 Lingulida - Lingulidae
Lingula ? subspatulata Hall and Meek 1855
originally entered as "Lingula ? subspatulata"
 Sabellida - Serpulidae
 Arcida - Arcidae
 Myalinida - Inoceramidae
Inoceramus fragilis Hall and Meek 1856 clam
Inoceramus fragilis Hall and Meek 1856 clam
mesabiensis, n. var.
 Pectinida - Pectinoidae
Pecten platessus scallop
(Camptonectes); possibly more than 1 var.
 Pectinida - Limidae
Lima utahensis file clam
 Pectinida - Anomiidae
 Ostreida - Gryphaeidae
Exogyra boveyensis oyster
n. sp.
Exogyra lamellosa oyster
n. sp.
Exogyra mesabiensis oyster
n. sp.
 Ostreida - Ostreidae
Ostrea congesta Conrad 1843 oyster
Ostrea gilei oyster
n. sp.
Ostrea staufferi oyster
(Alectryonia) n. sp.
Ostrea sp. Linnaeus 1758 oyster
 Ostreida - Pteriidae
Pteria gastrodes pearl oyster
 Ostreida - Bakevelliidae
Gervillia ? propleura oyster
originally entered as "Gervillia ? propleura"
 Ostreida - Pinnidae
Pinna sp. Linnaeus 1758 oyster
 Mytilida - Mytilidae
 Pholadida - Corbulidae
 Pholadida - Pholadidae
 Cardiida - Arcticidae
? Etea sp. Conrad 1873 clam
originally entered as "? Etea sp."
 Cardiida - Mactridae
 Cardiida - Veneridae
Tapes sp. Mühlfeld 1811 venus clam
Legumen cf. planulatum venus clam
originally entered as "Legumen cf. planulatum"
 Cardiida - Tellinidae
Tellina calumetensis tellin clam
n. sp.
 Cardiida - Cardiidae
Cardium enstromi cockle
n. sp.
 Solenida - Pharidae
 Pholadomyida - Pholadomyidae
 Nuculida - Nuculidae
 Protobranchia - Yoldiidae
Yoldia calumetensis clam
n. sp.
Gastropoda indet. Cuvier 1797 snail
"Gastropod sp."
 Ptenoglossa - Epitoniidae
Epitonium sp. Bolten 1798 wentletrap
 Neogastropoda - Volutidae
Volutoderma dalli volute
 Stromboidea - Strombidae
"Fusus shumardi" = Rostellaria (Fusus)
"Fusus shumardi" = Rostellaria (Fusus) true conch
 Stromboidea - Aporrhaidae
Aporrhais nuptialis snail
? Aporrhais sp. da Costa 1778 snail
originally entered as "? Aporrhais sp."
Anchura grouti snail
n. sp.
 Naticoidea - Naticidae
Polinices concinna moon snail
Gyrodes conradi moon snail
 Heterostropha - Acteonidae
"Actaeon propinquus" = Acteon
"Actaeon propinquus" = Acteon snail
originally entered as "Acteon propinquus"
 Neritoidea - Neritidae
? Nerita minnesotensis snail
n. sp. - originally entered as "? Nerita minnesotensis"
 Seguenzioidea - Calliotropidae
? Calliomphalus colerainensis snail
n. sp. - originally entered as "? Calliomphalus colerainensis"
 Dentaliida - Dentaliidae
Dentalium sp. Linnaeus 1758 tusk shell
 Ammonitida - Engonoceratidae
"Epengonoceras cf. dumblei" = Metengonoceras
"Epengonoceras cf. dumblei" = Metengonoceras ammonite
originally entered as "Epengonoceras cf. dumblei"
 Ammonitida - Acanthoceratidae
"? Metacalycoceras sp." = Calycoceras Hyatt 1900 ammonite
originally entered as "? Metacalycoceras sp."
Acanthoceras sp. Neumayr 1875 ammonite
Metoicoceras bergquisti Cobban 1983 ammonite
originally entered as "Metoicoceras aff. swallovi"
Vertebrata indet. Lamarck 1801
shark and other fish teeth, fish scales and vertebrae, reptile teeth
 Ichnofossils -
? Teredolites sp. Leymerie 1842
originally entered as "? Teredolites sp."