Deep Gradient/Suspect Terrain and the Protogaea Civica I, II, II series are site-based projects investigating the geology of the San Francisco Bay region and central California. Both of these projects are precursors of a set of investigations, San Francisco Wharf Complex, 2008 - present, based upone research done under several grants and a Bernard Osher Fellowship at the Exploratorium, 2008-2012. The most recent form of this work is, San Francisco Wharf Complex / American Industrial Center Carbonate Group, 2015, also included in the Shear Zones group of extended work in ceramics/geology.

Deep Gradient/Suspect Terrain is derived from an earlier glass ship project, the third element of The Lahontan Group I-III, 1985-87 - Vanishing Ship: Greenhouse for Lake Lahontan, 1987. This group of related works reference the geology of Lake Lahontan, an ice age lake of northern Nevada. The kiln project, Ancient Shoreline: Island for Lake Lahontan, 1985, was the first of this series.

Protogaea Civica I, II, II are site-specific works that demarcate the geology beneath the flag pole or poles. The images on the flags are from symbols and patterns used on geology maps. The individual flags represent a predominate rock type of the site as well as the anthropocene built-environment using architectural symbology for the flag images.