Help ID possible fossilized egg from early ordovician layer 88mm X 68mm

[allanstaib]

Hello all, Hoping I've found a fossilized egg and looking forward to any comments others might have. The "shell" appears intact on one side of the object and is missing from the other side. There appears to be a distinct "shell" layer. Any comments would be appreciated. Object is 80 mm by 68mm at the widest point. The object was found in an eroding hillside in the Cotter/Jefferson City formation in North Central Arkansas (Ozarks). This places this area in the early Ordovician geologic period. Thanks for any comments!

Allan

[Fossildude19]

Looks like a sandstone Concretion to me.

Ordovician was way too early for eggs.

Regards,

[Scylla]

Tim is right if you're thinking bird or reptile egg. They have found trilobite eggs, but this is way to big to be one of those. Most Ordovician creatures probably layed eggs, but they would have been jelly like objects that would not preserve well at all. So this is probably a concretion, but look at the faunal lists for the area, it may be a mold or cast of something round, I have seen sponges that come out as round balls.

[abyssunder]

Welcome to the Forum!

I agree with the others. Not an egg, but a nice sedimentary concretion with a multi-layered structure created by concentric growth. The spherical or ovoid shape sometimes makes to believe that it is an egg. The upper part was probably more exposed to weathering than the lower part which remains for a longer time embedded in the sediment.

[allanstaib]

Thanks all! Very helpful! I've gone to Wikipedia and read up on concert ions and I'm certain the consensus is correct. I've found other objects that I now understand to be concretions. Really appreciate the responses!

[FossilDudeCO]

......They have found trilobite eggs, but this is way to big to be one of those....

I need a picture....I had NO IDEA!

[Herb]

possibly a sponge (Hindia, can you see any structures?) but mot likely a concretion

[vonfatman]

I had a "tooth" a while back that was vanquished back to concretion status in mere moments...but the good side, now we know what a concretion is and may get some goodies when they are opened!

Bob