Hill Annex Mine Fossil Gallery

Minnesota fossils from the Cretaceous era Coleraine Formation
found at the Hill Annex Mine State Park in Calumet, MN
and surrounding areas of the Mesabi Iron Range.

This website features photographs of fossils found while volunteering with the Hill Annex Paleontology Project.

The Hill Annex Paleotology project explores a geological layer in Minnesota called the Coleraine Formation. The Coleraine Formation contains fossils from the Cretaceous period approximately 90 million years ago. It was exposed by the mining activity on the Mesabi Iron Range over the past century.

The Hill Annex Paleotology project seeks to increase scientific and community knowlege of the fossil material from that era of Minnesota history.

This website consists mostly of photographs I took of fossils as I found them. Occasionally there are photos of fossils found by other people. This gallery does not represent the most interesting finds of this project. What this website does uniquely provide are photos of fossils as they are found "in situ" - as they appeared when I spotted them. This may be especially useful for any readers that plan to go fossil hunting at Hill Annex State Park.

This website also is dedicated to providing material on the history of the Mesabi Iron Range.

Please also see the links to scientific papers on the fossils of the Coleraine Formation. These are the same papers referenced by paleontologists publishing new discoveries.

Links to historical papers on mining and the geology of the Mesabi Iron Range are also included as associated topics.

Note this is a personal website not affiliated with any institution.
Rylan Bachman bachmary@hotmail.com

Last updated August 24, 2020

Ancient Earth Globe 90 Million Years ago

This virtual globe allows visitors to rotate the Earth and see how it appears at various points in time.

Half of Minnesota is under the Western Interior Seaway when the fossils on the Iron Range were deposited during the Cretaceous period.

Hosted by DinosaurPictures.org

History of Hill Annex Mine

Field Photos at Hill Annex Mine

See how the fossils look when we find them.

Minnesota's Fossil Crocodile

Fossil Fish Scales

List of Species Found in the Coleraine Formation

(Always Under Construction)

Microscope Photographs of the
Gastropod Riker Box Specimens

High Resolution Microscope
Photograph of a
Colorful Gastropod Fossil

Fossil Pinecone

Prehistoric Videos

Documentaries, Films, and Books that I've enjoyed.

Science Talks

Scientists talking about prehistoric subjects
Coming Soon

An introductory list of topics for further reading.

Always under construction

Calumet and Local History Links


Calumet Golden Jubilee 1909-1959
Published to celebrate the city of Calumet's 50th anniversary

This book describes the history of Calumet and the people of the city from the first settler in 1890 up to 1959.
I scanned this copy from the Calumet Public Library.

Note this is a large 171MB file and may be viewed easier downloaded rather than opened in the browser.


This thesis includes blueprints for buildings that are still standing as part of Hill Annex State Park.

The Development of the Hill Annex Mine
by Earl Emmet Hunner
Thesis submitted for the degree Engineer of Mines
University of Wisconsin


History lecture podcasts by historian Donald Boese for KAXE radio.

The Coleraine formation is named after the city of Coleraine.
The history of the adjacent city of Bovey is inseparable from the history of Coleraine.

Note: Archived on the Wayback Machine Internet Archive

Minnesota Geology Field Trip, Summer 2000 and Other MN DNR Workshops
by Arlyn DeBruyckere with Dr. Tim Kroeger and Dr. John Annexstad Bemidji State University
Includes information on Hill Annex Mine

Cretaceous Fossil Links

Hill Annex Mine Paleontology Project

Entry on Anchura Grouti
Gastropoda Stromboidea Website
The Cretaceous System in Minnesota (RI-05)
by Robert E. Sloan
Minnesota Geological Survey.
Retrieved from the University of Minnesota Digital Conservancy,
Interview with Robert E. Sloan
by Professor Joe Cain

Robert E. Sloan was a University of Minnesota paleontologist.
He wrote the definitive book "Minnesota Fossils and Fossiliferous Rocks."

Cretaceous of the Mesabi Iron Range, Minnesota
Harlan R. Bergquist
Journal of Paleontology
Vol. 18, No. 1 (Jan., 1944), pp. 1-30
Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas
By William A. Cobban and E. A. Merewether

A. Molluscan fossil record from the northeastern part of the Upper Cretaceous seaway, Western Interior by William A. Cobban.
B. Lower Upper Cretaceous strata in Minnesota and adjacent areas-time-stratigraphic correlations and structural attitudes by E. A. Merewether

Mid-Cretaceous ammonite zones, Western Interior, United States
By William A. Cobban
Bull. geol. Soc. Denmark, vol. 33, pp. 71-89, Copenhagen, September, 11th, 1984.
Bluff Country Fossils
Blog by Beverly Sandlin
Fossil hunting in Southeast Minnesota
Oceans of Kansas
Information on Cretaceous in Kansas.
By Michael J. Everhart
Adjunct Curator of Paleontology at the Sternberg Museum of Natural History in Hays, Kansas since 1998.
Twice President (2005 and 2015) of the Kansas Academy of Science.
Co-editor of the Transactions of the Kansas Academy of Science from 2006 through the present (2016)
Another Sternberg “Fish-within-a-Fish” Discovery: First Report of Ichthyodectes ctenodon (Teleostei; Ichthyodectiformes) with Stomach Contents
By Michael J. Everhart, Scott A Hageman, Brian L. Hoffman
Transactions of the Kansas Academy of Science 113(3 & 4):197-205 September 2010
Ichthyodectes is a fish that appears in Hill Annex Mine as well.
Minnesota Cretaceous Pine Pollen
By Richard L. Pierce
University of Minnesota
Science 04 Jan 1957: Vol. 125, Issue 3236, pp. 26
Terminonaris (Archosauria: Crocodyliformes): new material from Saskatchewan, Canada, and comments on its phylogenetic relationships
By Xiao-Chun Wu , Anthony P. Russell & Stephen L. Cumbaa
Journal of Vertebrate Paleontology Vol. 21 , Iss. 3,2001

Note: Full paper behind paywall
The prehistoric crocodile species Teleorhinus mesabiensis is mentioned in the abstract. It was discovered at Hill Annex Mine.

Minnesota Geology and Mining Links

Overview of the mineralogy of the Biwabik Iron Formation, Mesabi Iron Range, northern Minnesota
by Peter Mcswiggen, G.B. Morey
Regulatory Toxicology and Pharmacology
52(1 Suppl):S11-25 · November 2007
The Iron-bearing Rocks of the Mesabi Range in Minnesota
by Josiah Edward Spurr
Geological and Natural History Survey of Minnesota
The Mesabi Iron-bearing District of Minnesota
by Charles Kenneth Leith
United States Geological Survey
The Origin of Sedimentary Iron Formations: The Biwabik Formation of the Mesabi Range
by John Walter Gruner
University of Minnesota Ph.D. dissertation
Bulletin No. 38. The Stratigraphy and Structure of the Mesabi Range, Minnesota
by David A. White
Minnesota Geological Survey
Paragraph Biography of Earl E. Hunner
He was a chief engineer with Oliver Mining and pioneered the use of electricity in Mesabi range mining.
The Development of the Hill Annex Mine
by Earl Emmet Hunner
Thesis submitted for the degree Engineer of Mines
University of Wisconsin
Engineering features of Missabe Range mining
by Earl Emmet Hunner
Thesis submitted for the degree of Civil Engineer
University of Wisconsin
Iron ore reserves of the Mesabi Range, Minnesota
By R.W. Marsden
Minnesota Geological Survey