In a field, 1970s

Jim & Chester’s Garage posted this scenic sea of classics in a field somewhere sometime in the early 1970s. Normally a little googling turns up where and/or when mystery photos were taken, but we weren’t able to turn up any details on this one. Obviously it was parking for some event, though, and we like to imagine it was a motorsports event of some sort, similar to yesterday’s carspotting scene. What do you see here?