Wegener also noted that the continents move up and down to maintain equilibrium in a process called isostasy. As an example he cited the sinking of Northern Hemisphere lands under the weight of continental ice sheets in the last ice age, and their rise since the ice melted some 10,000 years ago.
Drill that is fitted with a Pipe provides effective connection to the rig surface equipment or application with the bit and the bottom hole assembly for the purpose of pumping the Drill fluid to the bit.
While the pump-drill and the bow-drill were used in Western Civilization to bore smaller holes for a larger part of human history, the Auger was used to drill larger holes starting sometime between Roman and Medieval ages. The auger allowed for more torque for larger holes.