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 bits are cutting tools used to create cylindrical holes, almost always of circular cross-section. Drill bits come in many sizes and have many uses. Bits are usually connected to a mechanism, often simply referred to as a drill, which rotates them and provides torque and axial force to create the hole.
A skid-steer loader with an earth auger attachment. An auger bit in a brace for woodworking. An auger is a drilling device, or drill bit, that usually includes a rotating helical screw blade called a flighting to act as a screw conveyor to remove the drilled out material. The rotation of the blade causes the material to move out of the hole being drilled.