More about hydraulic mining, including some corrections ...
· For him, hydraulic mining is a method and placer describes a type of gold deposit including both recent and ancient riverbeds. (Wilson, page 152) Another authoritative writer, Waldemar Lindgren, used "placer" in the same way (and "pay streak" also). In 1911 the Geological Survey published his opus, The Tertiary Gravels of the ...