Bloomsburg and Mifflintown Formations, undivided

Includes, in descending order, the Bloomsburg Formation (Sb) and the Mifflintown Formation--interbedded dark-gray shale and medium-gray fossiliferous limestone; equivalent to "McKenzie" and "Rochester" of earlier workers; not present east of Harrisburg.
State Pennsylvania
Name Bloomsburg and Mifflintown Formations, undivided
Geologic age Silurian
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale (Bed)Mifflintown Formation--interbedded dark-gray shale and medium-gray fossiliferous limestone
Minor
Sedimentary > Clastic > Mudstone (Calcareous)
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Carbonate > Limestone (Bed)Mifflintown Formation--interbedded dark-gray shale and medium-gray fossiliferous limestone;
References

Berg, T.M., Edmunds, W.E., Geyer, A.R., and others, compilers, 1980, Geologic map of Pennsylvania: Pennsylvania Geological Survey, 4th ser., Map 1, 2nd ed., 3 sheets, scale 1:250,000.

Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources, Miles, C.E., and Whitfield, T.G., compilers, 2001, Bedrock Geology of Pennsylvania, edition: 1.0, digital map, scale 1:250,000.

NGMDB product
Counties Bedford - Blair - Columbia - Franklin - Fulton - Huntingdon - Juniata - Lycoming - Mifflin - Montour - Northumberland - Perry - Snyder - Union