TY  - RPRT
TI  - The geologic time classification of the United States Geological Survey compared with other classifications, accompanied by the original definitions of era, period and epoch terms
AU  - Mary Grace Wilmarth
PY  - 1925
DO  - 10.3133/b769
UR  - https://pubs.usgs.gov/publication/b769
ID  - b769
ER  -