Although Abraham Lincoln’s birthday was last week, we honor him today, as will I, by looking at the building stone of the Lincoln Memorial. In January 1913, a federal commission approved architect Henry Bacon’s plan for the monument. In contrast with the common practice of using a steel infrastructure, Bacon proposed white marble walls, columns, and floors. His preferred stone was the Yule marble from Colorado.
Lincoln Memorial (From Wikipedia)
First described geologically in 1874, the Yule quarry had only opened in 1904 and few easterners had seen it. Bacon had visited it in 1912 on a trip west and was impressed both by its beauty and by the large blocks the quarry produced. One long-time supporter called the Yule the “whitest, prettiest, and all things considered, the best marble.”
The Yule marble was originally deposited as a fine-grained, limey mud in an open shallow sea 345 million years ago when water covered western Canada and most of the United States. Geologists call this rock the Leadville Limestone in Colorado. An intrusion of magma 32 million years ago generated the heat necessary to locally metamorphose the Leadville into marble.
The quarry is located about 30 miles west of Aspen, Colorado, at 9,300 feet above sea level. It is completely underground. Workers took the stone out of the side of a mountain through portals and lowered them down to a train,which carried the blocks another 3.5 miles to a mill. Final cutting and shaping required the largest mill in the world, as each of the 38 columns consisted of 25-ton blocks.
Yule quarry (From Wikipedia)
The contractor completed the shell (a nifty Flash program showing construction) of the monument in October 1917. World War I prevented a dedication from occurring until Memorial Day, 1922. Coincidentally, this was the same year that the Yule quarry started back in business after shutting down in 1917; in 1919, it had sold to a junk dealer at a sheriff’s sale. Still popular, the quarry provided a 56-ton block for the Tomb of the Unknown Soldier in 1931, but then closed again in 1941. One year earlier a major crack had appeared in the massive block.