related tags: 47382D 6A5F5E 877A7A 8D7374 9B9497 9E9197 C9BEC2 CFB8C1 alluvial blue clast clasts conglomerate conglomerates creek fan formation fox mount mt neoproterozoic pebble pebbles polylithic polymict precambrian proterozoic ridge rogers troutdale virginia 413934 676261