Mystery Fossils Found on Lake Michigan’s Oval Beach

The winds along Lake Michigan reveal many buried fossils I often find that I like to share with you, but sometimes they are a complete mystery. My hope is that somebody can wage a guess or provide a knowledgeable answer about the following mystery fossils below in the comment box.


Mystery Fossil 2

UPDATE: C. Chavez wrote me about Mystery Fossil #2: I believe your “Mystery Fossil 2″ is not a fossil, but a reductive rock. If you were to crack it open you’d find the perfect circle is actually a sphere. It is created by some foreign material that is introduced into the rock which results in bleaching. It is the same idea as if you were to put a drop of bleach on blue jeans and it would expand into a circle. We have many reductive rocks where I live in NM, but they are not common elsewhere. You can find me and many more people helping to identify fossils at “”. Thank you C. Chavez
Mystery Fossil 4
MYSTERY FOSSIL #5 (This sample not found on Lake Michigan Beach)

Update: The fossil above is a section of an extinct soft shell turtle


Halysites Chain Coral Uncovered

Golden Beach grass dune
Oval Beach Saugatuck, Michigan  (Winter 2012)

I was super excited to discover several fossils on Oval Beach in Saugatuck, Michigan, USA that are highly unusual to find in winter. The fossil below was lying under deep layers of sand, but luckily, the mild weather with minimal snowfall allowed winter winds to push sand off the under layers. Also contributing to fossil hunting were the low water levels from a long dry spell during summer 2012, which produced more beach to explore.

Halysite Coral
Halysites Chain Coral Fossil Found on Lake Michigan Beach

These fossil samples are extinct tabulate corals, reef building colony-type corals, Halysites, commonly called, Chain Corals. They are fairly easy to distinguish due to the chain-link raised marks for which they’re named.

Halysites Chain Coral Fossil Found on Lake Michigan Beach

In life, the extinct Halysites corals possessed small tubes where the jelly-like polyps resided. The coral polyps contained stinging cells for protection and also for siphoning plankton and organic matter passing by in the ocean currents. As the Chain Corals grew, they built up walls of tube-like chambers called theca which steadily multiplied while adding more links to the chain. In their heyday, they built large limestone reef structures on the seabed. They thrived especially during the Silurian period as far back as 425 million-years-ago!

Halysites Chain Coral Classification

Kingdom: Animal

Phylum: Cnidaria (means stinging animal)

Class: Anthozoa (means flower animal)

Order:  Tabulata (possess inner horizontal dividing walls from growth patterns)

Family: Halisitidae (means chain coral)

Genus: Halysites  Species: unknown

Halysites Chain Coral Rendering Showing Polyps Extended

Explore more Lake Michigan fossils in another photo-essay I provided, otherwise, keep scrolling!

All rights reserved © Fossillady 2011