Here is the image of what she found. Thank you for any suggestions!

It's not a fossil, I'm afraid, but a very interesting type of mineral growth called cone-in-cone structures. They can be made from a variety of crystal types, but often calcite, growing within a single layer in densely-packed concentric conical structures. How these form, exactly, I'll let someone else answer... it's fascinating to look into the possible interpretations, but an answer is beyond my pay grade!