<p>You don't say which lake, but these are almost certainly <a href="http://en.wikipedia.org/wiki/Crinoid" rel="nofollow noreferrer">crinoid</a> stem fossils. Crinoids, or sea lilies, are <a href="http://en.wikipedia.org/wiki/Echinoderm" rel="nofollow noreferrer">echinoderm</a>s (relatives of starfish and sea urchins) that anchor themselves to the sea floor and feed on plankton.</p>

<p>In some crinoids, the animal's sea urchin-like <em>calyx</em> is connected to the anchor by a long <em>stem</em> to a <em>holdfast</em> which anchors it. The stem part of the crinoid's <a href="http://en.wikipedia.org/wiki/Endoskeleton" rel="nofollow noreferrer">endoskeleton</a> is a stack of calcareous rings or pentagons (called "ossicles") which look almost like a little spinal column. (However, vertebrates are not descended from crinoids, even though Echinoderms are <a href="http://en.wikipedia.org/wiki/Deuterostome" rel="nofollow noreferrer">deuterostomes</a>, placing them closer to chordates than arthropods or molluscs). </p>

<p>When the animal dies, it falls into the bottom sediment and the stem can become disconnected as the sediment is compressed into limestone. Sometimes the rings stay aligned, and show assemblages like you see in your rock. Other times, all you see are disconnected rings or little pentagons, like the ones all over the rest of the rock.</p>

<p>Crinoids have been around since the <a href="http://en.wikipedia.org/wiki/Ordovician" rel="nofollow noreferrer">Ordovician</a> period 
485 million years ago, so they appear in (and sometimes entirely make up) limestones throughout the world.</p>

<p><a href="https://i.sstatic.net/xh1Lj.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/xh1Lj.jpg" alt="Crinoid fossils from Kansas"></a></p>

<p><sup>Source: <a href="http://www.kgs.ku.edu/Extension/fossils/crinoid.html" rel="nofollow noreferrer">GeoKansas</a></sup></p>

<p>And, just because it's there, here's <a href="http://youtu.be/cZcomBnNKXg" rel="nofollow noreferrer"> a video of a crinoid crawling across the sea floor</a>.</p>

CC BY-SA 3.0
2017-06-30T18:33:45.627Z
It should be mentioned that the individual rings and stars the OP sees in their rock are the individual segments of the stem, which come in variety of shapes and sizes. http://fosil.com.es/imagenes/Crinoideos.jpg
John
CC BY-SA 3.0
2017-06-30T22:02:09.963Z
@John It's in there.
Spencer
CC BY-SA 3.0
2017-06-24T21:37:44.460Z
2017-06-28T20:59:48.473Z
2017-06-28T20:59:48.473Z
Spencer
<p>I found this on Lake Ontario in Canada. I was wondering is there is anything special/out of the ordinary about it? </p>

<p><a href="https://i.sstatic.net/K17ot.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/K17ot.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-06-25T07:26:07.410Z
Nothing too unusual. Just looks like crinoid ossicles to me. Quite a nice example of lots of them still articulated though.
bon
CC BY-SA 4.0
2019-08-02T17:47:13.910Z
Obviously a prehistoric barcode :-)
jamesqf
<fossils>
What are these lines on this stone?
Magali
# What are these lines on this stone?

(Asked by: username_0 on 2017-06-24)

I found this on Lake Ontario in Canada. I was wondering is there is anything special/out of the ordinary about it?

[![enter image description here](https://i.sstatic.net/K17ot.jpg)](https://i.sstatic.net/K17ot.jpg)

**Tags:** fossils

> **Comments:**
> **username_1**: Nothing too unusual. Just looks like crinoid ossicles to me. Quite a nice example of lots of them still articulated though.  
> **username_2**: Obviously a prehistoric barcode :-)  

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## 1 answers

### Answer by username_3 on 2017-06-24. Score: 15

You don't say which lake, but these are almost certainly [crinoid](http://en.wikipedia.org/wiki/Crinoid) stem fossils. Crinoids, or sea lilies, are [echinoderm](http://en.wikipedia.org/wiki/Echinoderm)s (relatives of starfish and sea urchins) that anchor themselves to the sea floor and feed on plankton.

In some crinoids, the animal's sea urchin-like *calyx* is connected to the anchor by a long *stem* to a *holdfast* which anchors it. The stem part of the crinoid's [endoskeleton](http://en.wikipedia.org/wiki/Endoskeleton) is a stack of calcareous rings or pentagons (called "ossicles") which look almost like a little spinal column. (However, vertebrates are not descended from crinoids, even though Echinoderms are [deuterostomes](http://en.wikipedia.org/wiki/Deuterostome), placing them closer to chordates than arthropods or molluscs).

When the animal dies, it falls into the bottom sediment and the stem can become disconnected as the sediment is compressed into limestone. Sometimes the rings stay aligned, and show assemblages like you see in your rock. Other times, all you see are disconnected rings or little pentagons, like the ones all over the rest of the rock.

Crinoids have been around since the [Ordovician](http://en.wikipedia.org/wiki/Ordovician) period
485 million years ago, so they appear in (and sometimes entirely make up) limestones throughout the world.

[![Crinoid fossils from Kansas](https://i.sstatic.net/xh1Lj.jpg)](https://i.sstatic.net/xh1Lj.jpg)

Source: [GeoKansas](http://www.kgs.ku.edu/Extension/fossils/crinoid.html)

And, just because it's there, here's  [a video of a crinoid crawling across the sea floor](http://youtu.be/cZcomBnNKXg).

> **Comments:**
> **username_4**: It should be mentioned that the individual rings and stars the OP sees in their rock are the individual segments of the stem, which come in variety of shapes and sizes. http://fosil.com.es/imagenes/Crinoideos.jpg  
> **username_3**: @username_4 It's in there.  

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