Basalt pillars

In addition to erratics, there are other rocks standing out, basalt pillars.

Image … r-channels

The early evening light casts a warm glow on the basalt pillars of Frenchman Coulee, a popular rock-climbing site, in the Quincy Wildlife Area near Vantage. The unique pillars were formed millions of years ago as lava extruded through the Earth’s crust cooled, and later were further sculpted by massive ancient floods. … rt17.shtml


The Twin Sisters
Image … sters.html

The question is, why didn’t these get eroded as well? Or at least why didn’t they get toppled over by the flood?