Chert from
USA | |
| Econ Geol (1992) 87:2023-2040 Flohr, Marta J. (1990) Microbanded manganese formations Huebner, J. Stephen protoliths in the Franciscan Complex, California USGS Professional Paper 1502. |
| Econ Geol (1992) 87:2023-2040 |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |