The old timers typically washed these areas down to bedrock, and some areas appear terraced. I would imagine this is because these hydraulic mines were generally where the miners found old Tertiary river channels on the sides of mountains that were gold-bearing.

It is not necessary to have a PhD in geology, but you need to know the basics, so that’s what I am going to try to dig into here—the understandable basics of these gigantic gold deposits.