The Roosevelt Arch, at the north entrance to Yellowstone Park, was built in 1904 with TR himself laying the cornerstone.
The arch is built from basalt column segments quarried somewhere in the park.
Notice that the corners and arches were chiseled rectangular while the remainder of the columns remain polygonal, with the pointed sides exposed.
I can’t find any record of where the basalt was quarried, or who the stonemasons were.
One possibility is that the basalt was quarried from the Swan Lake Flat Basalt about 12 miles to the south.
