The Construction of Mt. Rushmore: The monument was sculpted by Borglum and about 400 stone workers. Construction began on August 10, 1927 (President Coolidge attended the dedication that day). Funding was provided by private donations and the Federal Government.

The sculpting was done by first blasting away tons of rock with dynamite. Workers then sat in hanging "swing seats," and used jackhammers, drills, hammers, and other tools to do the finishing work. Bad weather and a lack of funding slowed work; although it took 14 years to finish the project, work was done for only about 6 of those years.

After Borglum's death, soon before the sculpture was done, the completion of the giant sculpture was overseen by his son, Lincoln Borglum. The monument was completed in 1941 (after Borglum's death).

Geology of the Area: The rock of Mt. Rushmore consists of outcroppings of fine-grained granite (a hard, light-colored, igneous rock - volcanic rock that has cooled) and some mica schist (a type of crystalline metamorphic rock). The light-colored granite of Mt. Rushmore contrasts with darker layers of mica schist. Mt. Rushmore is the northeastern edge of the Harney Peak Granite Batholith (a batholith is a huge body of igneous rock that solidified under the earth).