I've finally found them, knew they were here all along, just not exactly where.
There's a small cave under the highway - somewhere near Banff, it's not so much a cave as a rock overhang, and the rocks that have fallen from the top have piled on the bottom and make a sort of lip, and I'm hiking into it when I notice that the ceiling of the overhang is nothing but trilobites. Giant trilobites, like the impression of horseshoes in the limestone, hundreds of them, some are huge, several feet long, others are smaller. And everywhere, neatly piled, are the trilobites chipped from the rock that tourists took home with them, then felt guilty about taking and returned later. Some have been polished and look quite nice, I'm excited about this discovery, am looking through the countless trilobites when I hear a warden coming...
I crawl back further into the cave and crouch down behind a pile of rocks...There is no law against being here, but my intent is transparent...