Hi Richard. My first hikes in the Heather Meadows/Table Mountain area were in the early ’80s, so I can’t speculate on wildlife back in the ’60s. I can’t think of anything that might fit your description aside from a bear, mountain lion, or wolverine. I also haven’t heard of any unusual incidents of wildlife encounters in that area. Heather Meadows, Artist Point, and Table Mountain are heavily used in all seasons, so I would assume most wildlife avoid the area. In all my visits to this area, I haven’t seen or heard any wildlife there other than a pika.

Although I’ve heard talk about it over the years, I wasn’t aware of any agency actively reintroducing grizzlies into the North Cascades. Wildlife biologists are certain of a small population of grizzlies in the North Cascades, but as far as I know, there has been only one confirmed sighting. That was around ten years ago, and the photo I saw was a somewhat distant silhouette of a bear. In my opinion, it looked like it could easily have been a fake. I’ve come across only five or six black bears in nearly my forty years of hiking in the North Cascades. Maybe that makes me lucky or oblivious to wildlife when I’m out hiking.

You might want to check the forums at http://www.nwhikers.net, there may be someone there that has more expertise in the matter than I. Sorry I couldn’t be of more help.
Alan