What kind of rock is this?

how big is it? a coin next to it ould help.

Also, theres a piece of granitic rock next to this specimen. Is this area a jumble of all kinds of rock?
Where abouts are you located (country- nd region).
The focused fossil seems to be a scallop hell

The whole thing is double the size of a baseball.

The granite you are seeing is my countertop.

The fossil is about the size of a quarter.

It was found in southern Ontario, Canada.

Thanks!