Conglomerate from Black Hills, USA
USA | |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| KellerLynn, K. (2009) Wind Cave National Park Geologic Resources Inventory Report. Natural |
| Richardson G. B., (1903), The Upper Red Beds of the Black Hills, The Journal of Geology, Vol. 11, No. 4 (May – June). |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |