Nope, I'm not a son or a grandson. He is my namesake. My father named me for Mark after reading Jim Gasque's "Hunting and Fishing in the Great Smokies". I still have his 1st edition, autographed by the author. It was one of his favorite books, and he passed it on to me on my 18th birthday. The last time I was in BC, there was an older lady working at the Pizza Hut there who's father had been a good friend of Cathey's.
You can hear a brief snippet of him speaking here:
I wrote a little bit about my father's fascination with him a couple of years ago here:
My father fly-fished the smokies from his teenage years until right before he passed away in 2006 at the age of 76. He was as fine a fly fisherman as I've ever seen on the river.