Newbie find

[Ninadanner]

Taking my son for a nature hike yesterday morning, trying to inspire a love for the outdoors onto him. We ID everything we find, but this is our first fossil! Found this deep in the woods in millstone, Monmouth county. Spoke to two paleontologists, one said pycnodonte and the other said Ostrea. Help! I don’t know anything about fossils. 

[Shellseeker]

Welcome to the Fossil Forum,  someone here can help in identification

Both Pycnodonte and Ostrea are included in the Oyster seashell family and even though my avatar is Shellseeker, it takes skill to differentiate between them.  One of those is @MikeR

[Tetradium]

2 hours ago, Shellseeker said:

Welcome to the Fossil Forum,  someone here can help in identification

Both Pycnodonte and Ostrea are included in the Oyster seashell family and even though my avatar is Shellseeker, it takes skill to differentiate between them.  One of those is @MikeR

From what I knows its usually the general shape of the shell and the muscle scars that can sometimes tell the genus apart. But fossil ones are harder. For example with modern oysters Eastern Oyster Crassostrea always have colored muscle scars despite the huge variability in shapes. One or two other oysters which are similar in Florida  Ostrea have white muscle scars.  From what I have seen goggle image Ostrea is generally flatter or have wavy edges while Pycnodonte is more cupped and deeper.