TY  - RPRT
TI  - Preliminary map of diatremes and alkalic ultramafic intrusions in the Missouri River Breaks and vicinity, north-central Montana
AU  - B. C. Hearn
PY  - 1979
DO  - 10.3133/ofr791128
UR  - https://pubs.usgs.gov/publication/ofr791128
ID  - ofr791128
ER  -