I've written over the years about efforts related to geoheritagetreating rock formations and landforms like endangered species. The May issue of the SIPES Quarterly newsletter
(PDF) has an exploration in some depth of a proposal to launch a geological version of the Nature Conservancy. The author, Thomas Ewing, says that the prominent "geosites" like the Grand Canyon are in good hands as national parks and World Heritage sites. But he argues that multitudes of "less glamorous but equally important fossil localities, stream bluffs, quarry walls and roadcuts" need care and protection as well. More "geological landmark" designations in existing parks would be useful too, he says. SIPES is the Society of Independent Professional Earth Scientists, a largely Midwestern group generally focused on the energy industry.
Geological World Heritage Sites
UPDATE: Garry Hayes, of the Geotripper blog, has chimed in and helpfully added three worthy candidates for geosites. Every geologist has a similar list.
Cinder cone cross section, Cascade Range Geology Guide photo