Volcanic activity eons ago laid down this substantial granite deposit known as the Shonkin Sag Lacolith. Geologists Louis N. Pirrson and Walter H. Weed named the gray stone “Shonkinite” in 1894. I. E. Jenkins and W. H. Guyor began formal quarrying in 1914. They named the company after their hometown of West Quincy, Massachusetts, America’s “granite capital.” Two companies quarried granite from the two tiers of the outcrop, employing twenty-seven workers at the peak. Boulders scattered at the base of the upthrust provided enough stone for local needs and for buildings as far away as Denver. The cliff itself was never quarried. Brothers J. Arthur and Paul Rudin along with Carl Johnson, all natives of Sweden by way of Massachusetts, leased the West Quincy Quarry in 1916. They marketed their stone as “Lone Tree Granite” after the nearby ranch and former stage stop. Rudin Bros. Granite Co. supplied the stone for buildings, monuments, and engraved markers across Montana, including the boulder that marks renowned artist C.M. Russell. In 1928, the Tanners, Lone Tree ranchers, purchased the quarry land and then leased it to the Rudin Bros. After Art Rudin’s death in 1939, Johnson and Rudin’s two sons operated the quarry. Johnson purchased the business in 1943, operating it into the 1960s. Square Butte granite has fueled the local economy and has long adorned Montana’s buildings, cemeteries, and monuments.