From findagrave.com:

Birth: Jan. 24, 1843
Richmond
Richmond City
Virginia, USA
Death: Dec. 6, 1922
Charlottesville
Charlottesville City
Virginia, USA

Civil engineer; During the Civil War, Bolton served the Confederacy by helping to lay out defenses around Richmond, supervising and constructing the Piedmont Railroad from Danville, Virginia, to Greensboro, North Carolina, and constructing and subsequently destroying a pontoon bridge over the Potomac River following the retreat from Gettysburg; Following the war, he designed a 600 foot railroad tunnel under Gamble’s Hill in Richmond (1866-1867) and a 4000 foot tunnel under Church Hill (1872-1873). From 1876 to 1879 he was in charge of constructing a canal around the cascades of the Columbia River in Oregon, and in 1907 supervised construction of two railroad tunnels in the Rocky Mountains in Montana.