Aerial photo of Shaw Butte in central Montana, U.S. It shows the dike that once provided magma to Shaw Butte. This ridge was the magma pipe feeding the intrusion. It moved from nearby Adel Mountain volcanic field to the location of what is now a laccolith (Shaw Butte) through a crack in the bedrock. The layers of the covering rock have been eroded since, exposing the "plumbing" system. (© Bob Rumney, Rumney Cattle Co., via <a href="http://formontana.net/5.html" target="_blank">formontana.net</a> by Rod Benson)