Callan Bentley (November 14, 2011). "Compton Peak: superb columnar jointing". Callan Bentley's blog Mountain Beltway on American Geophysical Union Blogosphere. Retrieved July 24, 2015.
"Archived copy"(PDF). Archived from the original(PDF) on September 1, 2010. Retrieved August 31, 2010.{{cite web}}: CS1 maint: archived copy as title (link)
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"Archived copy"(PDF). Archived from the original(PDF) on September 1, 2010. Retrieved August 31, 2010.{{cite web}}: CS1 maint: archived copy as title (link)