We just got back from the Denver show, and while we were there we picked up this really nice fish fossil plate from Lebanon.  What makes it special is that one of the 3 fish is supposedly a Dogfish.  Unfortunately, we didn't get much other information from the dealer, so I'm hoping someone here can help us out with a few questions:   1.  Any idea what species this dogfish is, and is this technically a shark or is it a relative of a shark?   2.  Any idea what the age would be?