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Identifying the Fossils and Corals (Crinoids, Bryozoans, Etc.) on the Beach of Lake Michigan

Author:

Kathi writes about fossils and other earthly subjects, plus the natural history of Michigan, poetry, and more.

One favorite pastime for many is combing the beaches to find what interesting things the surf washes in. Whether you're walking along the shoreline of the ocean or of one of the Great Lakes, you may be looking to pick up something you just can't let go!

Something catches your eye. It's not driftwood or beach glass or even a pretty rock. You suspect you have found something that was once a living creature.

I Found a Fossil on the Beach

Has that ever happened to you? A deep sense of curiosity and childlike imagination may drive you to find out what you picked up on the beaches of our freshwater and saltwater shorelines.

Having collected quite a few samples from Lake Michigan's shoreline, I decided to fulfill my nagging curiosity and followed through with a rewarding investigation. The more I learned about my stony sand-smoothed findings, the more I wanted to know. I wondered what those creatures may have looked like when alive and how they lived. I also wanted to know how they showed up so prevalent along our fresh water beaches. After many answered questions, I can honestly say I now enjoy a cool hobby. Taking things a step further, I have drawn illustrations of their living beings and started a more in-depth fossil blog of all my discoveries.

Below, you will find information about all of my favorite beach fossil finds,

  • crinoids,
  • bryozans,
  • brachiopods,
  • clam fossils,
  • Petoskey stones,
  • stromatolites,
  • and favosite, horn, and chain corals,

with photos and colorful illustrations.

Crinoids

Crinoid Fossils Embedded in Lake Michigan  Brownstone

Crinoid Fossils Embedded in Lake Michigan Brownstone

Finding a Crinoid on the Shore

Some of the most common fossils found along the Great Lake's beaches are crinoids (shown above). They have been coined with a several names due to the animal's features and the character of their fossils. One common name for them is "Indian Beads," as Native Americans were known to make necklaces with crinoids which resemble the shape of cheerios, perfect for stringing. They've also been referred to as "Lucky Stones"! Spotting one takes a keen eye as most of the pieces are quite small.

Crinoid Fossil Stems and Individual Pieces Found on Lake Michigan Beach

Crinoid Fossil Stems and Individual Pieces Found on Lake Michigan Beach

Lake Michigan Scattered Crinoid Pieces Embedded in Prehistoric Ocean Floor

Lake Michigan Scattered Crinoid Pieces Embedded in Prehistoric Ocean Floor

About Crinoids

As living creatures, each circular section was stacked over another, constructing the animal's entire framework. They possessed branching arms that sat atop of long single stems. They were sessile creatures—in other words, they remained attached to the sea floor. Some varieties are known to have towered several meters in length. Their loose structure resulted in the living organism's beautifully colored and flowerlike appearance which granted them the nickname of "Sea Lilies." They captured tiny food particles passing by on ocean currents with their feathery network of arms that functioned like traps. Crinoids fit into the phylum of Echinoderm, meaning spiny skin, and are cousins of starfish, sea urchins, and feather stars.

Sea lily crinoid's lengthy history began during the Ordovician Period around 500 million years ago, although most fossils are from the Mississipian Period around 345 mya and are preserved in limestone. Today there are far fewer species and most lack the long meandering stem common in Paleozoic varieties.

Rendition of Paleozoic Crinoids

Rendition of Paleozoic Crinoids

Why Are Saltwater Crinoids Found In Fresh Water?

I often wondered why so many crinoid fossils ended up along the beaches of the freshwater Great Lakes, especially since they had thrived in saltwater environments. The answer is easy enough to explain. During the "sea lily" crinoid's lifetime, much of the world's continents were covered under warm, shallow, saltwater oceans where their living species died and settled on the ocean bottom buried in sediment. Millions of years later, they fossilized. Prehistoric fossilized remains have been discovered widespread throughout North America.

I still wondered why their fossils are so prevalent on the beaches of the big lakes? Here's why: ten thousand years ago when the giant glaciers sculpted the deep basins forming the Great Lakes, they also dug into the deep layers of sediment where crinoid remains rested. In the process, their remains were released and consequently, the constant wave action of the lakes continue to deposit them on the beach where we love finding them!

It's a satisfying feeling when something you've been curious about for a long time is finally realized!

Bryozoans

Bryozoan Fossil Lake Michigan Beach

Bryozoan Fossil Lake Michigan Beach

Bryozoan Fossil Lake Michigan Beach

Bryozoan Fossil Lake Michigan Beach

About Bryozoan Fossils

Another common beach find are Paleozoic Era "bryozoan" fossils, often called lace corals because of their delicately threaded appearance, although they were not true corals. Instead, they were moss-like animals belonging to the family of Fenestellida known for their fan-shaped, mesh-like appearance. They lived in tight colonies sculpted by hard, limy, branching structures. The colony consisted of thousands of individual animals called zooids. Each individual zooid lived inside its own limy tube called a zooecium. The zooecium were the size of sewing needles. A single zooid began the colony. A modern day bryozoan colony has been observed growing from a single zooid to 38,000 in just five months. Each additional zooid is a clone of the very first one.

It's interesting how they feed: Each zooid has an opening through which the animal can extend its ring of tentacles, called lophophores, to capture microscopic plankton. If one zooid receives food, it nourishes the neighboring zooids, because they are joined by strands of protoplasm. If only we humans could be more like them, ensuring everyone on the planet is fed!

Their fossil record dates back 500 mya, with 15,000 known species. Today there are about 3,500 living species.

Brachiopods

Brachiopod Fossil Lake Michigan Beach

Brachiopod Fossil Lake Michigan Beach

Brachiopods in the Ocean Mist Drawing

Brachiopods in the Ocean Mist Drawing

About Brachiopods

No other organisms typify the Age of Invertebrates more than brachiopods. They are the most abundant Paleozic fossils, except for maybe trilobites. Because of this, paleontologists use them to date rocks and other fossils. Countless billions accumulated on the ocean floor in over 30,000 forms. Today there are far fewer species, only about 300, which live mostly in cold, deep ocean environments.

Brachiopods look like clams but are very different inside. Clams have uneven-shaped shells, but both top and bottom halves are identical. Brachiopods are symmetrical at a glance, but the bottom shell is smaller. Brachiopods are commonly called "lampshells" due to their similarity in shape of a Roman oil lamp.

They live in communities attached to objects by a muscular foot called a pedicle. They strain water in and out of their shells, filtering microorganisms with their lophophores or crowns of tentacles.

Clams

Clam Fossil Lake Michigan Beach

Clam Fossil Lake Michigan Beach

Lake Michigan Beach Clam Shell Fossil

Lake Michigan Beach Clam Shell Fossil

Flip Side Lake Michigan Beach Clam Shell Fossil

Flip Side Lake Michigan Beach Clam Shell Fossil

About Clam Fossils

I found these clam fossils on the shore of Oval Beach in Southwestern Michigan. The shell of the darker sample has been completely replaced by minerals and is petrified to stone. It's likely the mold of the shell, where sediment and minerals permeated. Its smooth surface is a telltale demonstration of the lake's sand and water action. The lighter-colored sample clearly reveals the hardened muddy sediment that has completely encrusted its shell.

"Clam" can be a term that covers all bivalves. Some clams bury themselves in sand and breathe by extending a tube to the water’s surface. Bivalve oysters and mussels attach themselves to hard objects, and scallops can free swim by flapping their valves together. All types lack a head and usually have no eyes, although scallops are a notable exception. With the use of two adductor muscles, they can open and close their shells tightly. Very fittingly, the word “clam” gives rise to the metaphor “to clam up,” meaning to stop speaking or listening.

Bivalves have occupied Earth as early as the Cambrian Period 510 million years ago, but they were particularly abundant during the Devonian Period around 400 million years ago. Their fossils are discovered in all marine ecosystems and most commonly in near shore environments. In 2007, off the coast of Iceland, a clam was discovered that was estimated to be about 507 years old. It was declared the world’s oldest living creature by researchers at Bangor University in North Wales.

Petoskey Stone

Polished "Petoskey Stone" Coral Fossil

Polished "Petoskey Stone" Coral Fossil

"Petoskey Stone" Coral Fossil Unpolished

"Petoskey Stone" Coral Fossil Unpolished

"Petoskey Stone" Coral Fossil Worn Down by Natural Elements

"Petoskey Stone" Coral Fossil Worn Down by Natural Elements

About Petoskey Stone Corals

During the Devonian time, over 350 million years ago, Michigan was covered by a shallow saltwater sea. That's where mass colonies of corals called Hexagonaria percarinata, commonly known as Petoskey Stones, thrived and flourished. The saltwater seascape must have been lit up with a quiltwork of colors by their mass colonies. Unfortunately, they became extinct at the end of the Permian Period's mass extinction.

The name “Petoskey” originated from an Ottawa fur trader chief named Petosegay. A northern Michigan city was named after him, except the name was modified to Petoskey. Because the coral fossils are so abundant along Michigan shorelines, especially in the northern regions near the city of Petoskey, Governor George Romney signed a bill in 1965 making the Petoskey Stone the official state stone.

When observing one of these fossils, you'll notice each visible coral hexagon structure held a single animal which opened a mouth to expose tentacles. The tentacles took in food and were also used to sting any organism or other corallite that came too close. Calcite, silica, and other minerals replaced the original corallite exoskeleton. The last photo example above demonstrates Lake Michigan's natural polishing process from the wind, wave, and sand movement.

Ancient Seabed Drawing with Petoskey Stone Corals, Crinoids, Clams and Byozoans

Ancient Seabed Drawing with Petoskey Stone Corals, Crinoids, Clams and Byozoans

Favosite

Lake Michigan Beach Favosite Coral Fossil

Lake Michigan Beach Favosite Coral Fossil

Lake Michigan Beach Favosite Coral Fossil

Lake Michigan Beach Favosite Coral Fossil

About Favosite Corals

If you live in Northern Michigan, you come across these quite often. We living in the Southwestern Michigan find them occasionally on the lakeshore. Favosite is an extinct order of coral called tabulate corals which also formed reefs and lived in warm, shallow waters during the same period as the Petoskey Stone corals. The tabulae (horizontal internal layers) were built outward as the organism grew. These layers can clearly be seen in the photo above. The walls between each corallite (cup housing the individual animal polyp) are pierced by pores known as mural pores which allowed a transfer of nutrients between polyps. The favosites can be identified by the honeycomb pattern on the exterior of their fossilized remains.

Drawing Rendition of Favosite Coral

Drawing Rendition of Favosite Coral

Horn Corals

Lake Michigan Horn Coral Fossil

Lake Michigan Horn Coral Fossil

About Horn Corals

It's fun to find these curious coral fossils when beachcombing. Horn corals belonged to the extinct order of rugose corals which appeared as early as 450 million years ago until about 250 mya. That's an astounding 200 million years living on Earth. Their name derives from their unique horn-shaped chamber with its wrinkled (or rugose) wall. When viewed from its widest opening, it looks like a pinwheel where the coral polyps once poked out, sifting microorganisms passing by in the ocean currents. Some species grew two meters high up from the seafloor. They were mostly solitary, with a few exceptions that grew in mass colonies.

Drawing Rendition of Extinct Horn Corals

Drawing Rendition of Extinct Horn Corals

Chain Corals

Lake Michigan Chain Coral Fossils

Lake Michigan Chain Coral Fossils

About Chain Corals

The trail of chains in this beach-smooth limestone is another occasional fun find on the lakeshore. The chains are a dead give away for what's called "chain coral" from the Halysite family of the order Tabulate corals. This is another coral type that began its reign during the Silurian Period approximately 450 years ago. As with most coral polyps, they possessed stinging cells which also grasped plankton floating by in the currents. As their coral polyps continued to multiply, they added more links to the chain, sometimes building large limestone reefs.

Stromatolites

Lake Michigan Beach Stromatolite Fossil

Lake Michigan Beach Stromatolite Fossil

Lake Michigan Beach Stromatolite Fossil (Wet)

Lake Michigan Beach Stromatolite Fossil (Wet)

About Stromatolites

You're combing the beach in search of something interesting to examine. You pick up a common smooth stone, admiring its sleek texture. Little did you know, it's actually a fossil.

When wet, the stone reveals its layers of striations. It's a stromatolite fossil, the oldest of all fossils, dating as far back as 3.5 billion years ago. Their heyday was long before the Cambrian creatures evolved (stromatolites actually paved the way for their existence). Stromatolites were simple cyanobacteria capable of photosynthesis. Their structures grew solid, layered, and varied, some of which looked like giant mushrooms reaching eight feet tall. Through photosynthesis, they changed Earth's atmosphere from carbon-dioxide-rich to oxygen-rich. Scientists believed they were extinct before 1956, when living stromatolites were discovered in Shark Bay of Australia. Since then, there have been many more stromatolite discoveries around the globe.

The stromatolites forming today in the shallow waters of Shark Bay, Australia are built by colonies of microbes. Credit: University of Wisconsin-Madison

The stromatolites forming today in the shallow waters of Shark Bay, Australia are built by colonies of microbes. Credit: University of Wisconsin-Madison

Questions About Fossils

Which is the oldest fossil?

Stromatolites are the oldest of all fossils, dating as far back as 3.5 billion years ago.

Which fossils are the most common?

Brachiopod, Crinoid, and Bryozoan fossils, the first on this list, are the most common.

Which type of fossil has a honeycomb pattern?

Favosites can be identified by the characteristic honeycomb pattern on the exterior of their fossilized remains.

Why are saltwater fossils found near fresh water?

Thousands of years ago, when giant glaciers sculpted deep basins, they also dug into the deep layers of sediment to release fossilized remains.

What other types of rocks might I find on the beach?

Read Identifying the Rocks of Lake Michigan (Geode, Septarian, Agate, and More) to identify and learn about other rocks you might find on the Great Lakes.

© 2010 Kathi

Comments

KANWAL YOUSAFZAI from Pakistan on June 03, 2020:

Great research on fossils ,i appreciate your work Kathi.

Ryan on August 12, 2018:

How do post a picture of a rock (fossil) i found on WI shore?

suz on July 19, 2018:

I've been beachcombing for decades,

I am sure I have some gems of fossils

in my collections. I'm off to find them right now.

thanks for great info.

Always searching on July 06, 2018:

Thank you Kathi ,

Love to read this information. We spent a week on Beautiful Beaver Island and thus the fascination with beach stones , fossil, beach glass and the like began. Your description helped identify our Treasure. Thank you for sharing your knowledge. Your articles now appear in my Pinterest feeds ! Walking the beach, listening to birds and finding neat things does make me feel 12 . It is good for the soul !!

Greensleeves Hubs from Essex, UK on December 22, 2014:

Nice introduction to fossils and fossil hunting for beginners Kathi.

I like the line:

'A deep sense of curiosity and childlike imagination drives some of us to find out what we picked up along the freshwater shoreline.'

That's the unfortunate point I think. For some reason, as people grow out of childhood too many lose their childhood fascination for such things as fossils, as well as other wonders like the creatures which live in a pond, or the stars to be seen in the night sky. That's sad - if only everyone could keep that sense of curiosity and imagination as they grow up - the world would be a much more wondrous place for all - adults, as well as children.

I hope some at least feel inspired as they walk along a shoreline or beside a cliff face, to turn over a few stones and see what they can find. Alun

Kathi (author) from Saugatuck Michigan on April 21, 2013:

Thank you Ps... sorry I missed this so long ago! Appreciate you angels messages so much! Have a great week ahead! Kathi :O)

Patricia Scott from North Central Florida on February 27, 2013:

Yes, Fossillady, I did enjoy this. This has been an afternoon of learning. I have read so many interesting articles this afternoon and this one is definitely one I will remember. I had no idea. It is amazing how much there is to learn about fossils.

Voted up+++

Sending many Angels your way this afternoon. :) ps

Jon on April 08, 2012:

Thanks for the great resource. Been collecting fossils on the beach in Chicago for a year or so and your site and information is the best out there. Thanks!

Pete on March 03, 2012:

Hey this is so cool i just bought my first fossil and wana talk with people abot this stuff . someone text me haha

Kathi (author) from Saugatuck Michigan on June 21, 2011:

Hey Micky, good to see you, sorry so late as I've been so busy lately with new jobs and all! I miss the regular contact with all my hubber friends! Thank you for the great comment, you're very kind to say so! Hope everything is great with you! Hugs my friend

Micky Dee on June 19, 2011:

Your hubs are so pretty! Thank you dear Fossillady!

Kathi (author) from Saugatuck Michigan on May 10, 2011:

Ha, What do you know, I'm a geo-jokster and don't even know it...hee

tom hellert from home on May 10, 2011:

Ha fossillady something new...LOL and were talking about fossil Ha that's a great geo-joke...

Kathi (author) from Saugatuck Michigan on May 09, 2011:

Extremely pleased with this discussion Tom and Birdy, learned something new!!!!!

Brenda Barnes from America-Broken But Still Beautiful on May 08, 2011:

I guess it is like a tree with the circles. Interesting.

tom hellert from home on May 08, 2011:

All,

I am pretty sure the accretion lines on the top of a clam will reveal its age-like the rings on a tree the clam gets bigger and another ring is added-

TH

Brenda Barnes from America-Broken But Still Beautiful on May 08, 2011:

I will talk fossils with you any day. I am in touch with both sides of my brain! Sometimes I surprise myself, lol.

"In 2007, off the coast of Iceland, a clam was discovered to be at least 405 years old. It was declared the world’s oldest living creature by North Wales, Bangor University researchers." How do they know this and where is the clam at now? How does one determine the age of a clam that has seen centuries pass? Oh, I think a poem just came to mind. Both sides of that brain are reacting at the same time.

Thanks for a great and well researched Hub.

Kathi (author) from Saugatuck Michigan on April 28, 2011:

Very kind of you Janet! I had never worked with pastels before so there's lots of room for improvement, they are mostly targeted for children! Next time you're at the beach or in nature I hope you can recognize some of these fossils!

tumblintumblweed on April 28, 2011:

Very interesting hub,Fossillady !Very informative and I love the artwork! It's awesome.I never knew some of these were fossils! Well,I sure learned something tonight!

Thanks for sharing both info and art...nice combo!

TTW

tom hellert from home on April 28, 2011:

FL,

i know its kinda funny I always liked Ross too and my wife would always look at me when he would say something geological...

don't worry- post a fossily hub i'll read it...

ya got one fan...its a start

TH

Kathi (author) from Saugatuck Michigan on April 28, 2011:

I know what you mean, nobody wants to talk about fossils with me either. Reminds me of Ross on Friends. He always wants to share his information about fossils and the others won't have anything to do with it!lol

tom hellert from home on April 28, 2011:

FL,

I am just glad to talk fossils ith someone- my kids likem but.. even they tire of looking quick

TH

Kathi (author) from Saugatuck Michigan on April 28, 2011:

Great advice Tom, Very much appreciated!

tom hellert from home on April 23, 2011:

IZ, Wkmom,

When cleaning crinoids- ya gotta know what kinda rock is clinging to them- depends on the rock type you findem in around here it iseasily found in shale i usually rtry to clip off- the best i can with toe nail clippers - be careful- then i will use a pretty dilute HCL solution between .1 and .25 dilute-use a "soft wire brush" maybe nylon brush-ajust hcl to rockhardness- always use acid in wellventilated area use safety glasses and neoprene or nitrile gloves- sandstone embeds- can be picked off the crinoids and a final acid wash

TH

Kathi (author) from Saugatuck Michigan on April 23, 2011:

Hi Workingmom, Good to see you here! I wish I had advise for cleaning fossils, I would think as long as you don't use anything too harsh,it will be okay!

It sounds like it's not all that hard for you to find the crinoids where you are! I get so excited whenever I can spot one! lol...take care!

Mishael Austin Witty from Kentucky, USA on April 23, 2011:

Love this hub! I was actually thinking about writing a hub about crinoid beads (actually about using them to create jewelry, since I do that). My husband is an amateur archaeologist (aka rock hound), and he started taking me with him when we first started dating. I didn't care much about finding the arrowheads that he was hunting, but I fell in love with the beads! We were just down in Monroe Co., KY, and found quite a few within a few minutes by some of the many creeks. By the way, do you know a good method for cleaning fossils? I need to clean those beads if I'm going to make jewelry out of them!

Kathi (author) from Saugatuck Michigan on March 17, 2011:

Hi Tom,Oh it sounds like a rick fossil find area. I have never found a trilobite, my husband did once while working on the railroad. I like to find crinoids that are still attach, but it would be even better to find one fully intact! Thanks for stopping by!

tom hellert from home on March 17, 2011:

We have the sme devonian aged fossils near Lake Erie- that shallow sea was really big when my son went hunting with me he said what are all these nuts and washers doing here-on the ground of course we were in a crinoid rich area. There were a ton of Brac's s well-then we found some smaller trilobite halves and a had a great time diggin the dirt and shale shards He kept pulling up shale and asking what it was then he gave me one with a Trilobite trace fossil (imprint) it was really a good one

Kathi (author) from Saugatuck Michigan on March 13, 2011:

Hi WillStarr, You made your children feel very special that day! A wonderful fatherly thing to say. I would love to go to Kentucky and check out the shale bank. Kentucky has several fossil sites I've read about! I recognize you from other hubs and I see you're now following me, right back at ya!

WillStarr from Phoenix, Arizona on March 13, 2011:

The Kentucky farm where we lived for a few years had a shale bank on one side of a stream that was loaded with fossils. My children were fascinated when I told them they were looking at the beginnings of life on Earth, and that their eyes were the first human eyes to ever see what they had found.

Kathi (author) from Saugatuck Michigan on March 01, 2011:

Great, I'm glad you made a new discovery, I hope you find lots of fossils! It really is fun when you find one! It's gratifying later when you can identify it!

toknowinfo on February 28, 2011:

Wowwee! Great hub. I live in Long Island New York, where there are miles and miles of beaches. I never knew some of the things I was looking at could be fossils. When the weather is warmer I will revisit your hub to look and learn more. Thanks for educating me. Rated up and awesome.

Kathi (author) from Saugatuck Michigan on February 11, 2011:

My jaw dropped when you mentioned coelacanth fish that was found! I've read that too! I would love to come there and fossil hunt. I've never been across the ocean. Hope to do that before my day comes around!

Nell Rose from England on February 11, 2011:

Hi, you should come over to England, you would have a great time! lol the last time I went to Lyme Regis, Jurassic coast, they were filming for TV, and they had a fossil programme filled with all they had found, I would imagine that there are still loads of what we believe to be extinct animals still out there living in the deep ocean, I remember reading that fishermen found a coelacanth fish still living back in 1933, and I believe they have caught a few more since then, so you never know! cheers nell

Kathi (author) from Saugatuck Michigan on February 07, 2011:

Well, you have made my day and I hope yours is filled with love and joy! Hugs

BrendyMac on February 06, 2011:

Love this article very much...so informative..so interesting...and I love your little drawings as well as those awesome photos. I will be back for more and more!!?

Kathi (author) from Saugatuck Michigan on January 13, 2011:

As a matter of fact I am working on one partly thanks to your encouragement! It is much appreciated!

epigramman on January 12, 2011:

..Hello Kathi - yes I love to walk along my beach in the spring, summer and fall and pick up 'found objects' and flotsam and jetsam washed in from the tide especially after a storm or high winds but as I speak there is so much snow and ice down there right now you can't see anything except a big blanket of white - everywhere you look - I imagine I will have to wait until the spring now to discover anything new and get back to my days of 'beachcombing' .......if you have any more photographs about your days at the beach or just around where you live it would be nice to see you make another photographic hub on that subject ......

Kathi (author) from Saugatuck Michigan on December 13, 2010:

I can't help but feel sorry for poor deaf kitty, but I'm sure he/she's in good hands. We have the same lake effect on the west coast of Michigan caused by the westerly winds. In fact we're in a snow belt area. Last couple of years we've had record snowfall over 120 inches. Do you pick up fossils when you stroll the beach? Thanks again for your support!

epigramman on December 13, 2010:

...absolutely fascinating hub subject you have written about here .... I live on the northern shores of Lake Erie in Ontario, Canada and I walk everyday along my beach with my deaf cat (on a leash). I live 100 feet away from the lake ......and I always see flotsam and jetsam and found objects which are washed up on a daily basis whether it be man made or miracles of natures.

By the way how is the weather where you live?

We often get what is known as lake effect conditions because of the winds off the lake.

Again you have really done some wonderful research here on your hub and would be a worthy addition in any classroom!

Kathi (author) from Saugatuck Michigan on November 14, 2010:

Pheonix, sorry this response is so ridiculously late, but what did they ever find on the beach that day?

PhoenixV from USA on October 16, 2010:

Very cool hub , I have a friend I am going to show this to. They are probably on the beach right this minute on the west coast collecting shells as I write this!