Don "the Mudman" Myrah...
Note the barend shifters, this shot must be from the early or mid '90s as by the late '90s most riders had gone to STI.
Also interesting is the use of "natural features" as a barrier. Nowdays you get maybe 2 sets of 18" barriers per lap and maybe a run-up.
Yeah I have seen all those old grainy magazine scans from the '20s and '30s (very interesting stuff) but not a single contemporary photo of a really old bike. It just seems odd to me that you can find more pics of MTBs from the '70s than vintage cyclocross bikes. I have been scouring the web for cool vintage bike stuff for years and have as yet to see a good picture of a 'cross bike more than 10 or 15 years old and even those are like hen's teeth.