Reference | {Deposit:: PARKER, R.L. 1963, NIOBIUM AND TANTALUM IN THE UNIT ED STATES: USGS MAP MR-36}{Deposit:: TWETO, OGDEN, STEVEN, T.A., HAIL, W.J., JR., MOENCH, R.H., 1976, PRELIMINARY GEOLOGIC MAP OF THE MONTROSE 10 X 20 QUADRANGLE, SOUTHWESTERN COLORADO: USGS MAP MF-761, 1:250000} |