Yes midnight that is true, George Massey and his sons did find a glory hole on a river in the Northern California, under a waterfall.
They were dredging there for over a month, dredging through almost 20 feet of overburden, and got down to the bedrock and broke through a thick clay layer. The way Tom Massey tells it is that he just started dredging that morning and he found a large pocket of almond sized nuggets. he grabbed a handful and signaled to come up. When he broke the surface his dad wanted to know why came up so early Tom didn't say a thing he just held up the handful of nuggets. Then watched His Dads face turn white. In just a few days they found more gold than they did the whole month. It was the richest single strike they ever hit. When asked how much did they find he replied"Well I got a new Chevy Silverado".
The Canyon the waterfall was in is steep and narrow and nearly impossible to flume around it. The old timers missed it.