	Tysdal, Russell G., Ludington, S.D., McCafferty, Anne E. (1996) Mineral and energy resource assessment of the Helena National Forest, west-central Montana. Open-File Report Vol. 1996 (96-683) US Geological Survey doi:10.3133/ofr96683a	Report (issue)
	MINERAL AND ENERGY RESOURCE ASSESSMENT OF THE HELENA NATIONAL FOREST, WEST-CENTRAL MONTANA Edited by...Ludington2 , and A.E. McCafferty1 Open-File Report 96-683-A This report is preliminary and has not been... or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government... MINERAL AND ENERGY RESOURCE ASSESSMENT OF THE HELENA NATIONAL FOREST, WEST-CENTRAL MONTANA U.S. GEOLOGICAL...west-central Montana. It lies in the vicinity of Helena, the capitol city of Montana, and includes Federal
	*Barrell, Joseph (1907) Geology of the Marysville mining district, Montana; a study of igneous intrusion and contact metamorphism. Professional Paper* 57. US Geological Survey doi:10.3133/pp57**	Report (issue)
	B, Descriptive Geology, 113 Senes D, Petrography and Mineralogy, 34 Professional Paper No. 57 DEPARTMENT...THE MARYS,TJLLE NfiNING DISTRICT, ~IONTANA A STUDY OF IGNEOUS JNTH.USlON AND CON'l'ACT METAMORPHISM:...- - - - - •• - • - - - - - - - • - - Field work and acknowledgments. ________ :. ___________________.......... _........ _._ ..... __ . Climate, soil, and vegetation ...... -,- ............... _....... _..... __ . _. _____ .... __ . Age of river gravels and conglomerate .... _.. __ .... __ .. _._ .. _.. __
	Lewis, Richard Wheatley (1964) The geology, mineralogy and paragenesis of the Castrovirreyna lead-zinc-silver deposits, Peru. Open-File Report Vol. 1964 (64-103) US Geological Survey doi:10.3133/ofr64103	Report (issue)
	THE GEOLOGY, MINERALOGY, AND PAHAGENESIS OF THE CASTRDVIRHSYNA LEAD-ZINC-SILVER DEPOSITS, PERU By Richard...Wheatley Lewis, Jr. U. S. Geologic-1 Survey OPEN FIL3 HZfOR? This report is preliminary and ha_ not...Castrovirroyna mining district lies in the Andean Cordillera of South Central ?aru, and has been worked...first mined. Currently the district produces about 20,000 tons of laadsinc ore and* 50OO tons of silver ore...annually* The district: Is underlain by Tertiary andesitlc rocks interbedded with basalts and intruded by
	*Richardson, Lindsall (1933) The Country around Cirencester (Explanation of Sheet 235) Memoirs of the Geological Survey - England and Wales. Geological Survey of Great Britain*	Report (issue)
	OF SCIENTIFIC AND INDUSTRIAL RESEARCH MEMOIRS OF THE GEOLOGICAL ENGLAND AND WALES SURVEY EXPLANATION...contributions by Professor J. A. Hanley, A.R.C.S., Ph.D. and H. G. Dines, A.R.S.M. Crown Copyright Reserved ...of this district was shown on the Old Series Geological Map, Sheet 44, surveyed by E. Hull and published...with the local geology, and has made a special investigation of the Great Oolite and Forest Marble for the...place on record his appreciation of Hull’s work, and follows him in being of the opinion that it is best

Calcite from Little Ox Mine, Marysville Mining District, Lewis and Clark County, Montana, USA

Calcite from
Little Ox Mine, Marysville Mining District, Lewis and Clark County, Montana, USA