High Quality Content by WIKIPEDIA articles! Of Natural History is the second album by Avant-rock/metal group Sleepytime Gorilla Museum. It was recorded and mixed at Polymorph Recording in Oakland, California during the years 2003 and 2004. Whereas on the first album, Grand Opening and Closing, Dan Rathbun handled the mastering (in addition to producing, recording, and mixing), on Of Natural History the mastering duties are handled by Justin Weis, who mastered the album at Trakworx, San Francisco.