Lost Pet: George Silver

Circumstances

I took my indoor/outdoor cat to get some fresh air along the Mississippi River at the park underneath the 3rd Avenue Bridge in Minneapolis (close to a local hotel there). I?ve taken him camping many times and he has never gotten lost and always returned to me by nightfall, but this time I experienced an emergency and had to leave the area, after which I lost track of him and couldn?t find him when I returned. He is a very smart, independent, and self-sufficient cat, but I feel terribly about making such an irresponsible and foolish mistake in losing him. Please help me find him!