these are the other rocks I found near Lake Ontario enter image description here


closed as off-topic by user12525, Peter Jansson, Jan Doggen, arkaia, Fred Jul 13 at 17:18

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  • "Please review our rock identification guidelines to provide the missing information so that your question is both answerable and useful to new users." – Community, Peter Jansson, Jan Doggen, arkaia, Fred
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  • $\begingroup$ the markings are made by some biological prosses so it is off topic here,so it should be moved to biology section. $\endgroup$ – trond hansen Apr 2 '17 at 8:36

Your rock contains crinoid stems and coral fossils. The circular shape with star pattern is a cross sectional view of a crinoid stem. This patterns gives the fossil the nick name of 'star crinoid'.


Wikopedia has a good summary of crinoids.

Nice website on ontario fossils


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