Subsurface Rock Correlation Chart


Silurian to Ordovician Systems

Click for a PDF version of the diagram for these units (1.0 MB, opens in a new window).

 

Silurian System (405 – 430 MA)

 

SERIES

GROUP

FORMATION AND/OR UNIT

APPROXIMATE GEOGRAPHIC EXTENT

REFERENCES

 

Upper

 

Bass Islands Dol

Northwestern Pennsylvania, including portions of Erie, Crawford, Mercer, Venango, Warren, McKean, Forest, Elk, Butler, Clarion, and Armstrong Counties

M21, M73, PR178, SB10, SB11

 

Upper

Salina

G

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

Camillus Sh

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

F

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

E

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

E Sh

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

D

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

C Sh

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

B

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

A2

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

Salina

A1

Western and northcentral Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties; parts of Cameron, Clinton, and Lycoming Counties; and the eastern boundary of Tioga County

A64, A74ab, M21, M58, M73, PR178, SB10, SB11

 

Upper

 

Tonoloway Ls

Much of the study area, including parts of southwestern and central Pennsylvania

A64, A74ab, A86, M21, M73, SB10, SB11

 

Upper

 

Wills Creek Sh

Southwestern, southcentral, and portions of central Pennsylvania

A86, M73, SB10, SB11

 

Upper

 

Bloomsburg Fm

Central Pennsylvania, from Potter and Tioga Counties in the north to eastern Fayette, Somerset, Bedford, Fulton, and Franklin Counties in the south, and all those counties in between

A86, M73, SB10, SB11

 

Middle

 

Lockport Dol

Western Pennsylvania; eastern limit roughly follows central Fayette, Westmoreland, Indiana, and Clearfield Counties, and the western boundaries of Cameron and Potter Counties

M21, M73, PR178, SB10, SB11

 

Middle

 

Lockport Fm; DeCew Dol

Northwestern Pennsylvania, including parts of Erie, Crawford, Mercer, Venango, Warren, McKean, Forest, and Elk Counties

M21, M73, PR178, SB10, SB11

 

Middle

 

McKenzie Fm

Much of the study area, including southwestern and central Pennsylvania

A86, M73, SB10, SB11

 

Middle

Clinton

Irondequoit Dol

Northwestern Pennsylvania and much of western Pennsylvania

M21, M73, PR178, SB10, SB11

 

Middle

Clinton

Dayton Dol

Northwestern Pennsylvania and portions of western and southwestern Pennsylvania

M73, PR178, SB10, SB11

 

Middle

Clinton

Reynales Dol

Northwestern Pennsylvania and much of western Pennsylvania

M21, M73, PR178, SB10, SB11

 

Middle

Clinton

Rochester Sh

Entire study area

A86, M21, M73, PR178, SB10, SB11

 

Middle

 

Keefer Ss

Southwestern, southcentral, and portions of central Pennsylvania

A86, M73, SB10, SB11

 

Middle

 

Rose Hill Sh

Central Pennsylvania

A86, M21, M73, SB10, SB11

 

Lower

Medina

Grimsby Ss

Northwestern and western Pennsylvania, including Erie, Crawford, Mercer, Venango, Warren, McKean, Forest, Elk, Lawrence, and Beaver Counties

M21, M60, M73, M85, PR138, PR178, SB10, SB11

 
 
 

Lower

Medina

Cabot Head Sh

Northwestern and western Pennsylvania, including Erie, Crawford, Mercer, Venango, Warren, McKean, Forest, Elk, Lawrence, and Beaver Counties

M21, M60, M73, M85, PR138, PR178, SB10, SB11

 
 
 

Lower

Medina

Whirlpool Ss

Northwestern and western Pennsylvania, including Erie, Crawford, Mercer, Venango, Warren, McKean, Forest, Elk, Lawrence, and Beaver Counties

M21, M60, M73, M85, PR138, PR178, SB10, SB11

 
 
 

Lower

 

Castanea Member

Central Pennsylvania

A86, M73, SB10, SB11

 
 
 

Lower

 

Tuscarora Ss

Most of study area, with the exception of the areas described for the Grimsby Ss, Cabot Head Sh, and Whirlpool Ss above

A86, M73, SB10, SB11

 
 
 

SERIES

GROUP

FORMATION AND/OR UNIT

APPROXIMATE GEOGRAPHIC EXTENT

REFERENCES

 

Upper

 

Queenston Sh

Western Pennsylvania

M21, M73, PR178

 

Upper

 

Juniata Fm

Central Pennsylvania

A86, M73

 

Upper

 

Reedsville Sh

Entire study area

A86, PR178

 

Upper

 

Bald Eagle Fm

Central Pennsylvania

A86

 

Upper

 

Utica Sh

Entire study area

G49, PR178

 

Upper

 

Antes Sh

Central Pennsylvania

PR178

 

Upper

 

Trenton Ls

Western Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Black River Ls

Western Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Coburn Fm

Central Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Salona Fm

Central Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Nealmont Fm

Central Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Linden Hall Fm

Central Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Snyder Ls

Central Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Upper

 

Hatter Ls

Central Pennsylvania

Trenton Black River Field Trip Guidebook, G49, PR178

 

Middle

 

Loysburg Fm

Entire study area

Trenton Black River Field Trip Guidebook, G49, PR178

 

Middle

 

Loysburg Fm: Clover Member

Southcentral Pennsylvania, part of western Pennsylvania (including Butler, Clarion, Armstrong, Jefferson, and Indiana Counties), and part of northcentral Pennsylvania (Potter and Tioga Counties)

Trenton Black River Field Trip Guidebook, G49, PR178

 

Middle

 

Loysburg Fm: Milroy Member

Southcentral Pennsylvania, part of western Pennsylvania (including Butler, Clarion, Armstrong, Jefferson, and Indiana Counties), and part of northcentral Pennsylvania (Potter and Tioga Counties)

Trenton Black River Field Trip Guidebook, G49, PR178

 

Middle

 

Wells Creek Fm

Northwestern Pennsylvania, including Erie, Crawford, Venango, and Mercer Counties

G49, PR178

 

Middle

Beekmantown

Upper Bellefonte Dol

Most of the study area, with the exception of parts of northwestern Pennsylvania where the Wells Creek Fm is present

A86, G49

 

Middle

Beekmantown

Lower Bellefonte Dol

Central Pennsylvania

A86, G49

 

Lower

Beekmantown

Nittany Fm

Much of the study area, with the exception of Erie, Crawford, Mercer, Venango, Warren, McKean, Forest, and Elk Counties

A86, G49

 

Lower

Beekmantown

Larke Fm

Much of the study area, with the exception of Erie, Crawford, Mercer, and Venango Counties

G49

 
 

 

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