[VadeRetro]

Honestly, I've never considered that question. I know that mammoths haven't been discovered around dinosaurs, at least nearby.

There aren't any mammoths around trilobites, either.

[DittoJed2]

Incorrect. A mammoth was found in Newark, Ohio- Ohio being a prime area for Trilobites.

[DittoJed2]

Incidentally, if you are referring to layer, trilobites were sea creatures (interesting they are found in great numbers in Ohio) and Mammoths were land. Trilobites would naturally be at a bottom layer while mammoths would be higher up since the trilobite was already in the water.