Says I have to register, and I don't feel like registering...but anyway...Probably wouldn't be that unlikely to find a coral skelton that's only 4myo. 4my in a geological time scale is mearly a blink of an eye. If I remember right "coral reefs" have been on earth for in the order of 300?-400?my. Was an article (I believe this months) in RK magazine about coral evolution, pretty interesting.
I've found what I believe are a few fossilized coral skeltons here on the ranch, pretty darn cool...
-Dino-
Edit: This doesn't have to do with coral skeletons, but probably interesting to a few folks. Also on the ranch here I've found REALLY large fossilized mussle shells. One piece I have, if it was complete would measure pretty close to 3ft long. Also I've found large ammonite shells that are probably 1.5ft across (for you that don't know what a ammonite is, its from what I've read an extinct relative of the nautilus).