Oct
30
2008

Collecting fossils in Minnesota

Lilydale quarry: Located across the river from downtown St. Paul, Lilydale is probably the most famous fossil collecting site in the Twin Cities. Rock from the fossil-rich site was quarried by the now-defunct Twin Cities Brick Company and used for making bricks.
Lilydale quarry: Located across the river from downtown St. Paul, Lilydale is probably the most famous fossil collecting site in the Twin Cities. Rock from the fossil-rich site was quarried by the now-defunct Twin Cities Brick Company and used for making bricks.Courtesy Mark Ryan
Earlier this week a story appeared in the Minneapolis Star Tribune about fossil hunting in Lilydale Regional Park just across the river from the Science Museum. This has been a long-time favorite site to collect fossils from Minnesota’s ancient past. I’ve collected there often and at other sites around the region.

Fossil cephalopods: Specimen on the left was found at the Lilydale Quarry site. The slab on the right contains two small cephalopod fossils and was found near Shadow Falls in St. Paul, MN. Late Ordovician.
Fossil cephalopods: Specimen on the left was found at the Lilydale Quarry site. The slab on the right contains two small cephalopod fossils and was found near Shadow Falls in St. Paul, MN. Late Ordovician.Courtesy Mark Ryan
Ordovician fossils: Typical fossil-filled shale slab found around the Twin Cities’ fossil collecting areas. Late Ordovician.
Ordovician fossils: Typical fossil-filled shale slab found around the Twin Cities’ fossil collecting areas. Late Ordovician.Courtesy Mark Ryan
About 450 million years ago, the North American continent was situated along the equator, and a warm shallow sea covered much of Minnesota. Sea life was abundant as confirmed by the tremendous amounts of marine fossils that be found around here. Rock formations of sandstone, limestone, and shale line the Mississippi River. The layers are flat and fairly undisturbed from when they were laid down during the Ordovician Period. Most of the fossils come out of the Decorah shale and Platteville limestone.

Shadow Falls: Marcus Kenney and sons Elijah and Benny hunting for fossils at Shadow Falls. The easily accessed site is located near the Mississippi at the west end of Summit Avenue in St. Paul, MN.
Shadow Falls: Marcus Kenney and sons Elijah and Benny hunting for fossils at Shadow Falls. The easily accessed site is located near the Mississippi at the west end of Summit Avenue in St. Paul, MN.Courtesy Mark Ryan
I’ve been collecting fossils in this area for over three decades, and autumn has always been my favorite time to get outdoors, soak up some sun, and hunt for the elusive trilobite, or monstrous cephalopod (one of the largest found can be seen in the Science Museum’s Dinosaurs & Fossils gallery). You don’t really need much equipment, just a good eye, and maybe something to carry what you collect. Sometimes I like to have a mat or something to kneel on, but that’s me. I’ve been out quite a few times in the last six months and have found some very nice specimens.

Elusive trilobite: Molted trilobite tail. Trilobites are highly coveted by collectors. Late Ordovician
Elusive trilobite: Molted trilobite tail. Trilobites are highly coveted by collectors. Late OrdovicianCourtesy Mark Ryan
The Minnesota Geological Survey has plenty of information about Minnesota’s geology and prehistoric past. Click on the link to download their publication titled Fossil Collecting in the Twin Cities Area. It includes various collecting sites around southeastern Minnesota and illustrations of the fossils you’re likely to find there, such as bryozoans, brachiopods, gastropods, trilobites, horn coral, pelecypods, and cephalopods.

LINKS
Fossil collecting Lilydale Regional Park (pdf file)
Minnesota Fossils
More trilobite info
List of fossil sites and equipment
More about horn coral

Roadside attraction: Pat Ryan hunts for fossils in the Decorah shale outcropping in a highway ditch near Cannon Falls, MN. The highly fossiliferous site is located about 2 miles southeast of the town center.
Roadside attraction: Pat Ryan hunts for fossils in the Decorah shale outcropping in a highway ditch near Cannon Falls, MN. The highly fossiliferous site is located about 2 miles southeast of the town center.Courtesy Mark Ryan
More than enough fossils: Close-up of fossils littering the ditch near Cannon Falls, MN. Fossils at this site are found mostly weathered out of the matrix allowing for the collection of some great individual specimens.
More than enough fossils: Close-up of fossils littering the ditch near Cannon Falls, MN. Fossils at this site are found mostly weathered out of the matrix allowing for the collection of some great individual specimens.Courtesy Mark Ryan

Trapped in time: Fossil of a cephalopod (possibly baculites?) in situ, near Cannon Falls, MN. Late Ordovician.
Trapped in time: Fossil of a cephalopod (possibly baculites?) in situ, near Cannon Falls, MN. Late Ordovician.Courtesy Mark Ryan
Fossil of Ordovician predator: Fossil cephalopod (possibly baculites?) collected near Cannon Falls, MN.  Late Ordovician. Baculites were ammonites with a straight tusk-like shell. The cephalopods occupied the top of the food chain during the Ordovician.
Fossil of Ordovician predator: Fossil cephalopod (possibly baculites?) collected near Cannon Falls, MN. Late Ordovician. Baculites were ammonites with a straight tusk-like shell. The cephalopods occupied the top of the food chain during the Ordovician.Courtesy Mark Ryan
Fossil coral: Fossil coral (Favosites?) found near Cannon Falls, MN. Late Ordovician. Other than cephalopods, this is the largest single fossil I’ve ever found in the Decorah shale. I believe it’s some sort of striated coral.
Fossil coral: Fossil coral (Favosites?) found near Cannon Falls, MN. Late Ordovician. Other than cephalopods, this is the largest single fossil I’ve ever found in the Decorah shale. I believe it’s some sort of striated coral.Courtesy Mark Ryan
Lots of fossils: Bryozoa litter the ground at an exposure near Cannon Falls, MN. Bryozoa were microscopic animals that often formed coral-like colonies or fan structures and are the most common fossils found in the Decorah shale around southeast Minnesota.
Lots of fossils: Bryozoa litter the ground at an exposure near Cannon Falls, MN. Bryozoa were microscopic animals that often formed coral-like colonies or fan structures and are the most common fossils found in the Decorah shale around southeast Minnesota.Courtesy Mark Ryan
Down and dirty: Pat Ryan digs out a cephalopod fossils found on the flats of a Decorah shale exposure near Cannon Falls, MN.
Down and dirty: Pat Ryan digs out a cephalopod fossils found on the flats of a Decorah shale exposure near Cannon Falls, MN.Courtesy Mark Ryan
Close-up of cephalopod: Large cephalopod segment found by my brother Pat at Decorah shale exposure near Cannon Falls, MN. Another piece of the same specimen was found about 2 feet away.
Close-up of cephalopod: Large cephalopod segment found by my brother Pat at Decorah shale exposure near Cannon Falls, MN. Another piece of the same specimen was found about 2 feet away.Courtesy Mark Ryan
Rare find: Trilobite head in matrix, found near Cannon Falls, MN. Late Ordovician. Heads of the ancient arthropods are extremely rare. This is only the second trilobite head I’ve found in three decades collecting fossils around the Twin Cities
Rare find: Trilobite head in matrix, found near Cannon Falls, MN. Late Ordovician. Heads of the ancient arthropods are extremely rare. This is only the second trilobite head I’ve found in three decades collecting fossils around the Twin CitiesCourtesy Mark Ryan

Your rating: None Average: 4.8 (19 votes)

Your Comments, Thoughts, Questions, Ideas

DO's picture
DO says:

I was told (by a U of M geologist) that spring is to best time to fossil hunt since the freezing and thawing cycle over winter loosens the rocks so more surface is available.

posted on Fri, 10/31/2008 - 2:53pm
charger4264's picture
charger4264 says:

Yes the spring is a great time to go fossil hunting, but any time will work. Best after a rain allow the ground to dry and then have fun.

posted on Tue, 10/22/2013 - 6:23pm
Ahus1102's picture
Ahus1102 says:

I never new there was this kind of fossills in MN.

posted on Sat, 11/01/2008 - 7:08pm
Anonymous's picture
Anonymous says:

Cool! Fossils!

posted on Sat, 11/08/2008 - 3:23pm
Anonymous's picture
Anonymous says:

I think fossils and sfuff are cool but i dig them up for a living

posted on Sun, 11/09/2008 - 1:17pm
Anonymous me's picture
Anonymous me says:

where did you find these

posted on Wed, 04/15/2009 - 1:11pm
mdr's picture
mdr says:

Most of the fossils pictured were found around Cannon Falls, MN.

posted on Wed, 04/15/2009 - 3:52pm
Anonymous's picture
Anonymous says:

hey i live by cannon falls!!!

posted on Thu, 04/16/2009 - 9:45am
ART's picture
ART says:

I live in SE MN, and am wondering if one of the rocks I have found is an actual fossil, my son and I found one that has what appears to be a perfect imprint of a half of a moth or butterfly, is this possible? We found it in a rock pile at a roofing company, which by the way is a GREAT place to look for rocks if you have access!

posted on Mon, 08/24/2009 - 10:04pm
Joe and Candie's picture

I'm blogging photos of fossils found in the southeastern corner of the state. I have been to Lilydale and most of the sites around Cannon Falls and Wangs but I've had the most success finding my own locations. It appears that once a site has been documented on the web it gets picked clean. Most of the fossils we've found are from sites within 30 minutes of Rochester. Please feel free to check out our finds at http://coolfossils.blogspot.com/
Fossil Cephalopod Rochester MN: 19 inch Cephalopod found in Rochester Minnesota
Fossil Cephalopod Rochester MN: 19 inch Cephalopod found in Rochester MinnesotaCourtesy Joe Weston

posted on Wed, 11/10/2010 - 4:13pm
fl's picture
fl says:

im 11, and i love to look for fossils! it is my hobby! i hope to be a geologist someday!

posted on Fri, 06/24/2011 - 9:13pm
Connor's picture
Connor says:

Is this fossilized Coral?

http://farm7.static.flickr.com/6162/6235323291_f71b4934bc_b.jpg

posted on Tue, 10/11/2011 - 11:02pm
mdr's picture
mdr says:

It looks like a coral. Where did you find it? How big is it?

posted on Wed, 10/12/2011 - 6:13pm
eagleithall's picture

See video
i was wondering if you could help me id this "rock" i found in chaska mn,thanks

posted on Tue, 10/18/2011 - 6:30am
mdr's picture
mdr says:

My initial thought seeing the rock is that it may be a piece of material from the lining of a kiln or oven of some sort. Like a cinder created during the process of firing clay into bricks. Chaska was known for its brick manufacturing in the past. However, I've forwarded the video to someone else to get their opinion. Any further information you can supply? Where did you find it?

posted on Tue, 10/18/2011 - 2:51pm
eagleithall's picture

thanks,i found it in an area that is on the edge of a swamp bog type area,and the edge of an old farm field,which it has been since back to the mid 1800's it was around a couple of big old dead or dieng trees lot of other "normal" rocks around,nothing even close to this one,thanks again tom

posted on Wed, 10/19/2011 - 10:05am
Anonymous's picture
Anonymous says:

I cant find fossil hunt because im disablesd

posted on Thu, 12/01/2011 - 9:32am

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