Geology of the Area:
During the Paleozoic and Lower Mesozoic eras, the Pacific plate moved towards and under the edge of the continental plate, which created an offshore trench. The heterogenous, folded and faulted strata at the edge of continental plate, created by the tectonic movements, are ‘melange’. The exposed outcroppings have been dated to the Jurassic period.
Abundant Jurassic plant fossils have been reported to be “1 km S of old Banner Mine on River bank … on N side of Feather River SE of South Table Mountain”.
Additionally, a fossil bearing limestone deposit has been reported to be “on a hill just north of the Middle Fork of Feather River, 2 ¾ miles west of Nelson Bar bridge”.
Jurassic plants, and invertebrates.
Clarence A. Logan, “Limestone in California,” (California Journal of Mines and Geology, Vol. 43, No. 3, July 1947) <http://quarriesandbeyond.org/states/ca/quarry_photo/ca-plumas_photos.html>
“PALEONTOLOGIC RESOURCES IN THE VICINITY OF FERC PROJECT 2100 (OROVILLE RESERVOIR AND LOWER FEATHER RIVER): LITERATURE-BASED INVENTORY AND SIGNIFICANCE ASSESSMENT,” (California Department of Water Resources 2005) <http://www.water.ca.gov/orovillerelicensing/docs/wg_study_reports_and_docs/EWG/Paleontology%20jun03%20fr%20rev_public.pdf>
Donald Kenney, “US and Canadian Fossil Sites – Data for California.” <http://donaldkenney.x10.mx/STATES/CA.HTM>