 Construction resumed in 1879 under the direction of Lieutenant Colonel Thomas Lincoln Casey of the U.S. Army Corps of Engineers. Casey redesigned the foundation, strengthening it so it could support a structure that ultimately weighed more than 40,000 tons. He then followed the society's orders and figured out what to do with the memorial stones that had accumulated. Though many people ridiculed them, Casey managed to install most of the stones in the interior walls — one stone was found at the bottom of the elevator shaft in 1951. The bottom third of the monument is a slightly lighter shade than the rest of the construction because the marble was obtained from different quarries.
