TY  - RPRT
TI  - Map of rock types in bedrock of Allegheny County, Pennsylvania
AU  - W. R. Kohl
AU  - R. P. Briggs
PY  - 1975
DO  - 10.3133/mf685a
UR  - https://pubs.usgs.gov/publication/mf685A
ID  - mf685A
ER  -