Crinoids


Since I was a kid, I enjoyed finding these fossils. There was and is something cool to me about finding a fossil. Unfortunately, I never knew what type of fossil that I was finding. The kind of fossil that I found most often were the round fossils (usually about the size of a dime) with a hole in the middle. I have since discovered that these fossils were a small part of a organism known as a Crinoid that lived in the Ordovician period a long time ago (scientists estimate 542 to 488 million years ago). Thanks to paleophilospher for his comment regarding the period in which the Crinoids originally lived.

I have been combing the shore of the Tennessee River in Limestone County for the past few weeks. I have found several nice Crinoid fossils- including two different types of the Crinoids. The two types are the "sea lily" or Fixed Crinoid and the "Feather Star" or Free Swimming Crinoid.


The top photo is of a Fixed Crinoid. The stem is plainly visible. The cups located at the top part of the stem were known as the aboral cup. Arms would grow up from these cups- in the photo at the top you can see the indentions for at least two of these arms. See http://www.fossils-facts-and-finds.com/crinoid.html for an drawing of the completed plant.

The middle photo is of a Feather Star crinoid. I found it in a rock along the river bank as well. This is the only one of these that I have ever found.

The last photo shows a crinoid stem section. This is the most common fossil type found here in North Alabama.




9 comments:

paleophilosopher said...

Daniel,

The Cambrian period lasted from 542 to 488 million years ago, but most crinoid paleontologists believe that true crinoids did not appear until the Ordovician period, which lasted from 488 to about 443 million years ago.

Chris said...

Fossils are so neat! I love the "feather star" it looks like a perfect stamp! Nice find.

Steve said...

Daniel,
I remember finding the crinoids in my yard when I was a kid. It always amazed me that there were so many of these fossils. Also the fact that north Alabama is about 600 feet above current sea level. Also, I have never see the feather star either. Thanks for the posting the pictures.

Nature Nut /JJ Loch said...

Beautiful photos of fossils and a great post!

JJ :D

PLANET LEAH said...

Yes! I have found many of these crinoids in the backyard! I live in Trussville and estimate that 30-40% of the rocks have at least one crinoid in them around our property! It is bizzare!
Wow! had no idea they were that old!

nina said...

Great photos! Really enjoy your site.
Nina at Nature Remains

The Giraffe Head Tree said...

I'm also a fossil collector and have bowls of lakeshore objects sitting on a cabinet next to rocks from all over! Some people are just destined to be geeky - that's me! Great photos, Daniel. Now I want to go scour the riverbank for more ... stuff! Neighbor Debi

WildOrchid said...

I love fossil hunting! You've have some amazing finds. Have you ever looked around Seven Mile Island in Florence, Al? There is no digging allowed, but you are allowed to keep anything that has surfaced. I suggest going after a good rain. There's great wildlife there as well.

Lynne said...

I don't know who I am going to hear from I have those crinoid from Alabama. My family lives in Rogersville on the water and have a wonderful stream going through the property. We have made jewelry and have crinoids throughout my house. Anyone interested in these let me know.