Ted37 Posted January 6, 2019 Share Posted January 6, 2019 Went to look for shark teeth the other day on the potomac, md side. Found small teeth, and also a rock that looks interesting. Has some crystal or something on it. Any one have any ideas? Link to comment Share on other sites More sharing options...
Ted37 Posted January 6, 2019 Author Share Posted January 6, 2019 Another pic, it kind of looks like from a turtle. But, I am leaning toward a rock with some crystal formation on it. Link to comment Share on other sites More sharing options...
digit Posted January 6, 2019 Share Posted January 6, 2019 Looks like a bunch of Sand Tiger shark teeth. I was lucky enough to do some fossil hunting along the Potomac last year and this seems to be a common type of shark tooth from the Aquia Formation. Likely not turtle shell though I can see how the resemblance would lead you to that idea. I know that there is also a lot of fossilized shell material found in the area. You have the item in hand so maybe you can check closer and see if there are any indications of layering that might indicate part of a shell buried in matrix. If that does not seem to be the case, then my guess would be a crack in the rock that was infilled with a silica-rich material leading to a glassy later like that. Love the shark teeth. Cheers. -Ken Link to comment Share on other sites More sharing options...
caldigger Posted January 6, 2019 Share Posted January 6, 2019 Your "rock" looks like maybe oyster steinkern with some of the shell material still attached. 3 Link to comment Share on other sites More sharing options...
PaleoNoel Posted January 6, 2019 Share Posted January 6, 2019 Agreed, appears to be some oyster shell and matrix. Link to comment Share on other sites More sharing options...
Ted37 Posted January 6, 2019 Author Share Posted January 6, 2019 Newbie question, after reading the replies. So I may have an actual Oyster shell fossil that is wrapped around a rock? Or it is possible the entire piece may be a fossil? Or it could just be a rock with some crystal. I attached one more pic. Link to comment Share on other sites More sharing options...
caldigger Posted January 6, 2019 Share Posted January 6, 2019 Steinkerns are created when the fine sediments fill a shell after the animals death. The sediments harden and usually the shell desentagrates away leaving an internal cast of the shell shape. Yours appears to retain some of the shell which you are calling "crystals". Here are some common gastropod steinkerns above and a couple of bivalve casts below. Even though there is no original shell material remaining, they still hold the shape of the shells interior structure. For example: actual shell on the right, internal steinkern of a similar type gastropod on the left. The one on the left is from the Potomac River, Maryland. 5 Link to comment Share on other sites More sharing options...
Littlefoot Posted January 7, 2019 Share Posted January 7, 2019 I had no clue what a steinkern was until I joined this site! The people here know their stuff! I have some similar steinkerns of shells from Purse State Park, but not oyster shells. I especially like yours with the beautiful oyster shell coloring and the peek inside the rock area! That's a nice find! Link to comment Share on other sites More sharing options...
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