Bertie Formation

Geological formation in Ontario, Canada

Bertie Formation

Stratigraphic range: Pridoli (Cayugan Series)
~422.9–416.0 Ma

PreꞒ

Type| Geological group
Unit of| Cayugan Series
Sub-units| Falkirk (dolomite), Scajaquada (shale) and Williamsville (dolomite) - Western New York Fiddlers Green (dolomite), Forge Hollow (shale) and Oxbow (dolomite) - Central New York
Underlies| Bois Blanc Formation, Hederberg Group , Bass Islands Group
Overlies| Salina Group
Thickness| Up to 495 ft (151 m)
Lithology
Primary| Dolomite, Shale
Other| Shale
Location
Coordinates| 42°54′N 78°54′W﻿ / ﻿42.9°N 78.9°W﻿ / 42.9; -78.9
Approximate paleocoordinates| 30°18′S 40°48′W﻿ / ﻿30.3°S 40.8°W﻿ / -30.3; -40.8
Region| Ontario
New York
Country| Canada, United States
Extent| Appalachian Basin
Type section
Named for| Bertie, Ontario
Named by| Chapman
Year defined| 1864

Bertie Formation (the United States)

Show map of the United States

Bertie Formation (New York)

Show map of New York

The Bertie Group or Bertie Limestone, also referred to as the Bertie Dolomite and the Bertie Formation, is an upper Silurian (Pridoli, or Cayugan) geologic group and Lagerstätte in southern Ontario, Canada, and western New York State, United States. Details of the type locality and of stratigraphic nomenclature for this unit as used by the U.S. Geological Survey are available on-line at the National Geologic Map Database.[1] The formation comprises dolomites, limestones and shales and reaches a thickness of 495 feet (151 m) in the subsurface, while in outcrop the group can be 60 feet (18 m) thick.

The group represents the uppermost unit of the Cayugan Series and the youngest Silurian unit in Ontario. The group overlies the Salina Group and is conformably overlain by the Devonian Bois Blanc Formation in Ontario and Onondaga Limestone in New York.

Two formations within the Bertie Group, the Fiddler's Green and Williamsville, are considered Konservat-Lagerstätten; geologic units that contain a unique and typically soft-bodied fauna. These formations have produced thousands of Silurian eurypterids (sea scorpions) as well as early scorpion Proscorpius osborni, xiphosurans, primitive fossil flora, the planktonic cephalodiscid Rotaciurca superbus and the fish Nerepisacanthus denisoni. The excellent preservation of the many eurypterids and other taxa was the possibly result of periodic hypersaline and anoxic conditions owing to the group's position within a shallow inland sea (the Appalachian basin).

## Description

[edit]

The type locality for the Bertie Group is Ridgemount Quarry,[2] located west of Fort Erie on the Niagara Peninsula of Bertie, Ontario, 6 miles (9.7 km) west of Buffalo, New York,[3] after which the group is named.[4] The first author who recognized the group as a separate stratigraphic unit was Chapman in 1884.[3] In more recent years, the unit has been elevated to group status.[5][6]

## Geographic extent

[edit]

The Bertie Group forms the bedrock in a narrow band extending from Fort Erie, west of Buffalo, New York, through Hagersville, New Hamburg, Harriston, and Walkerton to Southampton on Lake Huron.[7] The group consists of medium- to massive-bedded aphanitic brown to grey, laminated, bituminous and burrowed dolomites,[8] with minor thin-bedded shaly dolomites.[9]

Along the outcrop area between Fort Erie and Hagersville, the thickness varies from 35 to 60 feet (11 to 18 m). It thickens to 495 feet (151 m) in the subsurface. Sanford (1969) used the term Bertie Group from Fort Erie to the vicinity of Hagersville and the term Bass Islands Formation north and west of Hagersville. The group is correlated with the Bass Islands Formation of Michigan. Bertie Group dolomite is quarried for crushed stone at Fort Erie, Port Colborne, Dunnville, Cayuga, and Hagersville.

## Stratigraphy

[edit]

The Bertie Group is the uppermost unit in the Cayugan Series and forms part of the Tippecanoe II sequence.[10] At its type locality, the group is subdivided into several formations.[3] In central New York, the Group is subdivided into the Fiddlers Green Dolomite, Forge Hollow Shale, and Oxbow Dolomite members, from oldest to youngest.[3] Here, the Bertie Group is overlain by the Honeoye and Chrysler formations. In New York, the Onondaga Limestone overlies the Bertie Group.[11] The group is in Ontario conformably overlain by the Middle Devonian Bois Blanc Formation.[12]

Laterally, the group is equivalent to the Bass Islands Formation and is mapped as a combined stratigraphic unit. Haynes and Parkins (1992) reported that the Bertie Group is progressively cut by the Bass Islands Formation from Dunnville to Hagersville.[8] In Pennsylvania, the Bertie Group is time-equivalent with the Keyser Formation.[13]

## Fossils

[edit]

Many Eurypterus fossils were found in the formation The fish Nerepisacanthus denisoni is the only vertebrate found in the Bertie Formation

The Bertie Group Fiddler's Green and Williamsville formations are considered Konservat-Lagerstätten;[14] units characterized by rare and typically soft-bodied fauna. These formations have produced thousands of fossil eurypterids (sea scorpions) since collecting began in earnest in the mid-20th century.[15][16] Other fossils from the unit include early scorpion Proscorpius osborni, early flora, and a fossil fish; Nerepisacanthus denisoni. The excellent preservation of the many eurypterids possibly was the result of periodic hypersaline and anoxic conditions.[17]

Group | Fossils | Member | Image | Notes

|
|
|
|

Fish | Nerepisacanthus denisoni | Williamsville |  | [18]
Eurypterids | Acutiramus macrophthalmus | Fiddlers Green
Williamsville |  | [19][20]
A. cummingsi | Fiddlers Green  |  | [21]
Buffalopterus pustulosus | Williamsville |  | [20][22]
Carcinosoma scorpionis | Oxbow Dolomite |  | [23]
Clarkeipterus testudineus | Fiddlers Green |  | [22][24]
Dolichopterus herkimerensis | Fiddlers Green |  | [22][24]
D. jewetti | Fiddlers Green | [25]
D. macrocheirus | Williamsville | [20][22]
D. siluriceps | Fiddlers Green
Williamsville |  | [20][21]
Erieopterus pustulosus | Fiddlers Green |  | [21]
Eurypterus dekayi | Williamsville |  | [20][26]
E. laculatus | Fiddlers Green |  | [27]
E. lacustris | Williamsville |  | [26]
E. remipes | Williamsville |  | [20][26]
Eusarcana scorpionis | Williamsville |  | [20]
Pterygotus cobbi | Williamsville |  | [20]
P. juvensis | Fiddlers Green | [21]
Erettopterus sp. | Fiddlers Green |  | [21]
E. grandis | Fiddlers Green |  | [21]
Rhinocarcinosoma sp. | Williamsville |  | [26]
Chasmataspidid | Diploaspis praecursor | Fiddlers Green |  | [28]
Planaterga | Bunaia woodwardi | Fiddlers Green |  | [21]
Limuloides eriensis | Fiddlers Green |  | [21]
Pseudoniscus clarkei, P. roosevelti | Fiddlers Green |  | [21]
Arachnids | Proscorpius osborni | Fiddlers Green |  | [29]
Artiopod | Naraoia bertiensis | Williamsville |  | [30]
Machaeridians | Lepidocoleus reinhardi | Fiddlers Green |  | [21]
Graptolites | Climacograptus ultimus | Fiddlers Green |  | [21]
Palaeodictyota buffaloensis | Fiddlers Green |  | [21]
Ascograptus sp. | Fiddlers Green |  | [21]
Orthograptus sp. | Fiddlers Green |  | [21]
Non-graptolite Pterobranch | Rotaciurca superbus | Williamsville |  | [31]
Crustaceans | Ceratiocaris acuminata, C. maccoyanus, C. praecedens | Williamsville |  | [32]
Emmelezoe minuta | Fiddlers Green |  | [21]
Gonatocaris sp. | Williamsville |  | [20]
Cephalopods | Dawsonoceras oconnellae | Fiddlers Green |  | [21]
Gomphoceras ruedemanni | Fiddlers Green |  | [21]
Mitroceras gebhardi | Fiddlers Green |  | [21]
Pristeroceras timidum | Fiddlers Green |  | [21]
Trochoceras cf. anderdonense | Fiddlers Green |  | [21]
Orthoceras sp. | Fiddlers Green |  | [21]
Phragmoceras sp. | Fiddlers Green |  | [21]
Gastropods | Loxonema bertiense | Fiddlers Green |  | [21]
Mesocoelia gregaria | Fiddlers Green |  | [21]
Platyceras (Platyostoma) sp. | Fiddlers Green |  | [21]
Bivalves | "Hercynella" buffaloensis | Fiddlers Green |  | [21]
Modiolopsis dubius | Fiddlers Green |  | [21]
Goniophora sp. | Fiddlers Green |  | [21]
Nuculites sp. | Fiddlers Green |  | [21]
Rhytimya sp. | Fiddlers Green |  | [21]
Ostracods | Eukloedenella umbilicata | Fiddlers Green |  | [21]
Leperditia alta, L. scalaris | Fiddlers Green |  | [21]
Zygobeyrichia cf. regina | Fiddlers Green |  | [21]
Polychaeta | Serpulites sp. | Fiddlers Green |  | [21]
Spirorbis sp. | Fiddlers Green |  | [21]
Rhynchonellata | Camarotoechia cf. andrewsi | Fiddlers Green |  | [21]
Reticularia (Prosserella) modestoidea | Fiddlers Green |  | [21]
Howellella eriensis | Fiddlers Green |  | [21]
Whitfieldella sulcata | Fiddlers Green |  | [21]
Delthyris sp. | Fiddlers Green |  | [21]
Edrioasteroidea | Pyrgocystis batheri | Fiddlers Green |  | [21]
Strophomenata | Schuchertella sp. | Fiddlers Green |  | [21]
Bryozoans | Hernodia sp. | Fiddlers Green |  | [21]
Reptaria sp. | Fiddlers Green |  | [21]
Stigmatella sp. | Fiddlers Green |  | [21]
Lingulata | Lingula semina, L. subtrigona | Fiddlers Green |  | [21]
Orbiculoidea cf. numulus | Fiddlers Green |  | [21]
Scyphozoa | Metaconularia perglabra | Fiddlers Green |  | [21]
Hydrozoa | Bertratis ciurcae | Williamsville
Fiddlers Green |  | [33]
Anthozoa | Aulocystis sp. | Fiddlers Green |  | [21]
?Ceratopora sp. | Fiddlers Green |  | [21]
Stromatoporoidea | Stromatopora constellata | Fiddlers Green |  | [21]
Dasycladophyceae | Medusaegraptus graminiformis | Fiddlers Green |  | [21]
Flora | Inocaulis lesqueureuxi | Williamsville |  | [34]
Cooksonia sp. | Williamsville |  | [35]
Hostinella silurica | Fiddlers Green |  | [36]
Cyanobacteria | Morania bertiensis | Fiddlers Green |  | [21]
Calithamnopsis silurica | Fiddlers Green |  | [21]

## Age

[edit]

The Bertie Formation is late Silurian (Pridoli, or Cayugan in the local chronologies).

## Interpretations of depositional environments

[edit]

See also: Geology of the Appalachians

The Appalachian Foreland basin was formed during the Alleghanian orogeny in the Early to Middle Ordovician. The period of mountain building led to the closure of the Iapetus and Rheic Oceans. Due to tectonic loading, the foreland basin developed in the present-day area north of the Appalachian Mountains.[37] The late Silurian climate was arid and warm; this, and the restricted and shallow nature of the inland basin, resulted in the deposition of evaporites in the Salina Group, ranging in thickness from 120 to 800 metres (390 to 2,620 ft).[38] Zones of stromatolites and thrombolites (non-laminated algal mounds) occur in several formations in the Bertie Group,[39] along with numerous desiccation cracks.[38] During the Hercynian orogeny in the Devonian, many of the Silurian sediments were eroded to the south in the Appalachians, while north of the mountains the Silurian units were preserved.[40]

The sediments of the Bertie Group were deposited on the paleosouthern side of the subsiding Algonquin Arch, flanking the northern rim of the Appalachian foreland basin of Laurentia.[14][41]

The Bertie Group was deposited in a hypersaline marine environment. The stratigraphic sections and the fossil content suggest that the group was deposited in a near-shore marine to lagoonal setting,[14] and the evaporites and casts of halite pseudomorphs, with sides of up to 30 centimetres (12 in), suggest the environment was far from normal marine; hypersalinity must have prevailed throughout most of the depositional history of the group.[42] Alternating hypersaline and brackish estuarine conditions have been recorded in the group.[14] The dolomitization of the group most probably was not primary.[43]

## See also

[edit]

* List of fossiliferous stratigraphic units in New York
* List of fossiliferous stratigraphic units in Ontario
* Tonoloway Formation, contemporaneous formation of Pennsylvania, Maryland, Virginia and West Virginia
* Tymochtee Dolomite, contemporaneous dolomite formation of Ohio
* Catavi Formation, contemporaneous fossiliferous formation of Bolivia
* Peel Sound Formation, contemporaneous fossiliferous formation of Nunavut, Canada
* Stony Mountain Formation, Late Ordovician Lagerstätte of Manitoba, Canada
* Lau event, Late Silurian extinction event preceding the Bertie fauna

## References

[edit]

1. ^ "National Geologic Map Database".
2. ^ Ridgemount Quarry South at Fossilworks.org
3. ^ a b c d Vrazo et al., 2017, p.5
4. ^ Sun et al., 2014, p.7
5. ^ Vrazo et al., 2014, p.431
6. ^ Edwards et al., 2004, p.399
7. ^ Hewitt, 1972, p.19
8. ^ a b Armstrong & Dodge, 2007, p.8
9. ^ Hewitt, 1972, p.10
10. ^ Swezey, 2002
11. ^ Rickard, 1969, p.4
12. ^ Hewitt, 1972, p.11
13. ^ Rickard, 1969, p.5
14. ^ a b c d Burrow & Rudkin, 2014, p.1
15. ^ Lau, 2009, p.10
16. ^ Vrazo et al., 2016, p.53
17. ^ Vrazo et al., 2016, p.58
18. ^ Burrow & Rudkin, 2014, p.2
19. ^ Eurypterid-Associated Biota of the Fiddlers Green Member, Herkimer Co., New York at Fossilworks.org
20. ^ a b c d e f g h i Eurypterid-Associated Biota of the Williamsville Member, Buffalo, New York at Fossilworks.org
21. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb Bertie at Fossilworks.org
22. ^ a b c d Lau, 2009, p.22
23. ^ Heard's Gypsum Quarry at Fossilworks.org
24. ^ a b Cranes Corners at Fossilworks.org
25. ^ Jerusalem Hill at Fossilworks.org
26. ^ a b c d Lau, 2009, p.21
27. ^ Eurypterids of the Fiddlers Green Member, Morganville, New York at Fossilworks.org
28. ^ Lamsdell, James C.; Briggs, Derek E. G. (2017). "The first diploaspidid (Chelicerata: Chasmataspidida) from North America (Silurian, Bertie Group, New York State) is the oldest species of Diploaspis". Geological Magazine. 154 (1): 175–180\. Bibcode:2017GeoM..154..175L. doi:10.1017/S0016756816000662. ISSN 0016-7568.
29. ^ Passage Gulf at Fossilworks.org
30. ^ Caron, Jean-Bernard; Rudkin, David M.; Milliken, Stuart (2004). "A new Late Silurian (Pridolian) naraoiid (Euarthropoda: Nektaspida) from the Bertie Formation of southern Ontario, Canada—delayed fallout from the Cambrian explosion". Journal of Paleontology. 78 (6): 1138–1145\. Bibcode:2004JPal...78.1138C. doi:10.1017/s0022336000043948. ISSN 0022-3360.
31. ^ Briggs, Derek E. G.; Mongiardino Koch, Nicolás (2023-11-06). "A Silurian pseudocolonial pterobranch". Current Biology. 33 (23): 5225–5232.e3. Bibcode:2023CBio...33E5225B. doi:10.1016/j.cub.2023.10.024. ISSN 0960-9822. PMID 37935193.
32. ^ Collette, Joseph H.; Hagadorn, James W. (2010). "Early Evolution of Phyllocarid Arthropods: Phylogeny and Systematics of Cambrian-Devonian Archaeostracans". Journal of Paleontology. 84 (5): 795–820\. Bibcode:2010JPal...84..795C. doi:10.1666/09-092.1. ISSN 0022-3360.
33. ^ Larson, Evelyn; Briggs, Derek E. G. (2023-12-01). "A hydrozoan from the eurypterid-dominated Silurian Bertie Group Lagerstätten of North America". Journal of Paleontology. 97 (5): 1002–1008\. Bibcode:2023JPal...97.1002L. doi:10.1017/jpa.2023.62. ISSN 0022-3360.
34. ^ Edwards et al., 2004, p.405
35. ^ Edwards et al., 2004, p.401
36. ^ Bertie Formation at Fossilworks.org
37. ^ Ettensohn, 2008, p.107
38. ^ a b Vrazo et al., 2016, p.49
39. ^ Brett et al., 1999, p.10
40. ^ Ettensohn, 2008, p.136
41. ^ Lau, 2009, p.24
42. ^ Forge Hollow, Waterville at Fossilworks.org
43. ^ Vrazo et al., 2016, p.56

### Bibliography

[edit]

* Armstrong, Derek K.; Dodge, J.E.P. (2007), Paleozoic Geology of Southern Ontario (PDF), Ontario Geological Survey, pp. 1–27, retrieved 2019-03-23
* Brett, Carlton E.; Goodman, William M.; Loduca, Steven T.; Tetreaul, Denis (1999), Silurian-Early Devonian sequence stratigraphy, events, and paleoenvironments of western New York and Ontario, Canada (PDF), NYSGA, pp. 1–58, retrieved 2019-03-23
* Burrow, Carole J.; Rudkin, David (2014), "Oldest Near-Complete Acanthodian: The First Vertebrate from the Silurian Bertie Formation Konservat-Lagersta¨tte, Ontario", PLoS ONE, 9 (8): 1–7, Bibcode:2014PLoSO...9j4171B, doi:10.1371/journal.pone.0104171, PMC 4122448, PMID 25093877
* Edwards, D.; Banks, H.P.; Ciurca, S.J.; Laub, R.S. (2004), "New Silurian cooksonias from dolostones of north-eastern North America", Botanical Journal of the Linnean Society, 146 (4): 399–413, doi:10.1111/j.1095-8339.2004.00332.x
* Ettensohn, Frank R (2008), "The Appalachian Foreland Basin in Eastern United States", K.J. Hsü: Sedimentary Basins of the World, Vol 5, the Sedimentary Basins of the United States and Canada, 5: 105–179, doi:10.1016/S1874-5997(08)00004-X, retrieved 2019-03-23
* Hewitt, D.H (1972), Paleozoic Geology of Southern Ontario (PDF), Ontario Division of Mines, pp. 1–19, retrieved 2019-03-23
* Lau, Kimberly (2009), Paleoecology and Paleobiogeography of the New York Appalachian Basin Eurypterids (BSc. thesis) (PDF), Yale University, pp. 1–48, S2CID 14229267, archived from the original (PDF) on 2018-02-28, retrieved 2019-03-23 Archived 2018-02-28 at the Wayback Machine
* Rickard, Lawrence V (1969), Stratigraphy of the Upper Silurian Salina Group New York, Pennsylvania, Ohio, Ontario (PDF), New York State Museum and Science Service, pp. 1–77, retrieved 2019-03-23
* Sun, S.; Brunton, F.R.; Jin, J. (2014), Sequence Stratigraphic Architecture and Bedrock Aquifers of Upper Silurian to Middle Devonian Strata, Southwestern Ontario, Ontario Geological Survey, Open File Report 6300, pp. 1–15, retrieved 2019-03-23
* Swezey, Christopher S (2002), Regional Stratigraphy and Petroleum Systems of the Appalachian Basin, North America (PDF), USGS, p. 1, retrieved 2019-03-23
* Treesh, Michael (1972), Sedimentology and Stratigraphy of the Salina Group (upper Silurian) in East-central New York (PDF), Rensselaer Polytechnic Institute, pp. 1–26, retrieved 2019-03-23
* Vrazo, Matthew B.; Brett, Carlton E.; Ciurca Jr, Samuel J. (2016), "Buried or brined? Eurypterids and evaporites in the Silurian Appalachian basin" (PDF), Palaeogeography, Palaeoclimatology, Palaeoecology, 444: 48–59, Bibcode:2016PPP...444...48V, doi:10.1016/j.palaeo.2015.12.011, retrieved 2019-03-23
* Vrazo, Matthew B.; Trop, Jeffrey M.; Brett, Carlton E. (2014), "A new eurypterid Lagerstätte from the Upper Silurian of Pennsylvania" (PDF), PALAIOS, 29 (8): 431–448, Bibcode:2014Palai..29..431V, doi:10.2110/palo.2014.003, S2CID 30066085, archived from the original (PDF) on 2019-03-09, retrieved 2019-03-23

## External links

[edit]

* The Eurypterida of New York/Volume 1
* The Eurypterida of New York/Volume 2

* v
* t
* e

Chronostratigraphy  of Michigan

Ph|

| Cz|

| Q|

| Pleistocene|

| indet.|

Glacial till

|

Pz|

| C|

| ⁋|

* Pewamo Formation
* Grand River Formation
* Saginaw Formation

|

indet.|

* Parma Sandstone

* Bayport Limestone
* Coldwater Shale
* Marshall Sandstone
* Sunbury Shale

| Upper|

| indet.|

* Antrim Shale
* Bedford Shale
* Berea Sandstone
* Ellsworth Shale

|

Frasnian|

* Squaw Bay Limestone

Middle|

| Givetian|

* Squaw Bay Limestone

|

* Alpena Limestone
* Amherstburg Formation
* Anderdon Limestone
* Bell Shale
* Bois Blanc Formation
* Dundee Limestone
* Ferron Point Formation
* Long Lake Limestone
* Lucas Formation
* Rockport Quarry Limestone
* Rogers City Limestone
* Sylvania Sandstone
* Thunder Bay Limestone

Lower|

* Garden Island Formation

| indet.|

* Bertie Formation
* Byron Formation
* Bush Bay Formation
* Cordell Formation
* Hendricks Formation
* Lime Island Formation
* Pointe aux Chenes Formation
* Put-in-Bay Dolomite
* Raisin River Dolomite
* Rapson Creek Formation
* Rockview Formation
* Salina Group
* Schoolcraft Formation
* St. Ignace Dolomite

|

Llandovery|

* Cabot Head Shale
* Manitoulin Dolomite

| Upper|

| Sandbian|

* Bill's Creek Shale

|

* Big Hill Formation
* Stonington Formation

Middle|

| Darriwilian|

* Bill's Creek Shale

|

* Black River Formation
* Collingwood Shale
* Trenton Formation

Lower|

* Au Train Formation

* Munising Formation

pЄ|

| ♇|

* Copper Harbor Conglomerate
* Freda Sandstone
* Jacobsville Sandstone
* Nonesuch Shale

|

* v
* t
* e

Chronostratigraphy of New York

Ph|

| Pz|

| D|

| Upper|

| Famennian|

* Cattaraugus Formation
* Chadokin Formation
* NE Shale
* Oswayo Formation
* Panama Conglomerate
* Perrysburg Formation
* Westfield Shale

|

Frasnian|

* Rhinestreet Formation
* Genesee Group
* Geneseo Shale
* Java Formation
* Sonyea Formation
* West Falls Formation

Middle|

| Givetian|

* Tully Limestone
* Hamilton Group
Moscow Formation
* Ludlowville Formation
* Skaneatales Formation

|

Eifelian|

* Marcellus Shale
* Onondaga Limestone
* Tioga Bentonites

Lower|

| Emsian|

* Bois Blanc Formation

|

| Pridoli|

* Bertie Formation

|

Ludlow|

| Ludfordian|

* Salina Group

|

Gorstian|

* Salina Group

Wenlock|

| Homerian|

* Salina Group

|

| Upper|

| Katian|

* Denley Formation
* Hillier Formation
* Indian Castle Shale
* Rust Formation
* Steuben Formation
* Sugar River Formation

|

Sandbian|

Trenton Limestone Group

* Kings Falls Formation

Black River Group
Lowville Formation

* Napanee Formation
* Selby Formation
* Sugar River Formation

* Black River Group

* v
* t
* e

Chronostratigraphy of Ohio

Ph|

| Pz|

| P|

| Cisuralian|

Dunkard Group
Greene Formation
Washington Formation

|

| ⁋|

| Gzhelian|

Dunkard Group
Waynesburg Formation

Monongahela Group
Uniontown Formation
Pittsburgh Formation

|

Kasimovian|

Conemaugh Group
Casselman Formation
Glenshaw Formation

Moscovian|

Allegheny Group
Pottsville Group

| Viséan|

* Maxville Limestone

|

Tournaisian|

Cuyahoga Formation

Logan Formation

* Sunbury Shale

* Coldwater Shale
* Rushville Shale

| Upper|

| Famennian|

* Bedford Shale
* Berea Sandstone
* Cussewago Sandstone

Ohio Shale
Cleveland Shale
Chagrin Shale
Huron Shale

|

Frasnian|

* Burket Shale
* Olentangy Shale (upper)

* Antrim Shale
* Java Formation

West Falls Group
Angola Shale
Rhinestreet Shale

Middle|

| Givetian|

* Tully Formation
* Mahantango Formation
* Olentangy Shale (lower)
* Plum Brook Shale
* Prout Limestone
* Silica Formation

|

Eifelian|

* Marcellus Shale

* Amherstburg Dolomite
* Columbus Limestone/Onondaga Limestone
* Delaware Limestone
* Detroit River Group
* Hillsboro Sandstone

* Dundee Formation
* Lucas Dolomite
* Tenmile Creek Dolomite

Lower|

| Emsian|

* Amherstburg Dolomite
* Detroit River Group
* Hillsboro Sandstone

|

Lochkovian|

* Holland Quarry Shale

* Bass Islands Dolomite
* Bois Blanc Formation
* Helderberg Group
* Oriskany Sandstone
* Sylvania Sandstone

| Pridoli|

* Bertie Formation

|

Ludlow|

| Ludfordian|

* Salina Group

|

Gorstian|

* Salina Group
* Guelph Dolomite

* Salina Group
* Greenfield Dolomite
* Tymochtee Dolomite

Wenlock|

| Homerian|

Lockport Group
Gasport Dolomite
Guelph Dolomite
Goat Island Dolomite

|

* Bisher Formation
* Cedarville Dolomite
* Dayton Formation
* Estill Shale
* Euphemia Dolomite
* Laurel Limestone
* Lilley Formation
* Massie Shale
* Osgood Shale
* Peebles Dolomite
* Rochester Shale
* Springfield Dolomite

Llandovery|

* Brassfield Formation
* Cabot Head Shale
* Clinton Formation
* Drowning Creek Formation
* Manitoulin Dolomite

| Upper|

* Arnheim Formation
* Cincinnati Group
* Drakes Formation
* Fairview Formation
* Grant Lake Formation
* Kope Formation
* Liberty Formation
* Miamitown Shale
* Queenston Shale
* Saluda Formation
* Trenton Limestone
* Waynesville Formation
* Whitewater Formation

|

Middle|

* Black River Group
* Lexington Limestone
* Point Pleasant Formation
* Trenton Limestone
* Wells Creek Formation

| Furongian|

* Conasauga Formation
* Eau Claire Formation
* Kerbel Formation
* Knox Dolomite
* Rome Formation

|

* Mt. Simon Sandstone

pЄ|

| ♇|

| Z|

* Swift Run Formation

|

* Middle Run Formation

* v
* t
* e

Chronostratigraphy of Pennsylvania

Ph|

| Pz|

| P|

| Cisuralian|

Dunkard Group

Greene Formation

*     Windy Gap Limestone
Windy Gap Coal
Gilmore Limestone
Nineveh Sandstone
Nineveh Coal
Nineveh Limestone
Fish Creek Sandstone
Claysville Limestone
Dunkard Coal
Prosperity Limestone
Tenmile Coal
Donley Limestone
Upper Washington Coal
Rockport Member

Washington Formation

*     Upper Washington Limestone Member
Jollytown Limestone Member
Jollytown Coal
Middle Washington Limestone Member
Washington Coal
Lower Washington Limestone Member

|

| ⁋|

| Gzhelian|

Dunkard Group

Waynesburg Formation

*     Upper Waynesburg Member
Little Washington Coal
Waynesburg“B” coal
Middle Waynesburg Member
Waynesburg“A” coal
Lower Waynesburg Member

Monongahela Group

Uniontown Formation

*     Waynesburg coal "No. 11 Coal"
Gilboy Sandstone Member
Little Waynesburg Coal
Waynesburg Limestone Member
Uniontown Sanstone Member
Annabelle Shale Member
Uniontown Coal "No. 10 Coal"
Uniontown Limestone Member "Great Lime"
Fulton Shale Member

Pittsburgh Formation

*     Benwood Limestone
Upper Sewickley Coal
Upper Sewickley Sandstone Member
Sewickley Coal "Meigis Creek" "No. 9 Coal"
Lower Sewickley Sandstone Member
Sewickley Limestone Member
Cedarville Sanstone Member
Redstone-Pomeroy coal "No 8a. Coal"
Westone Sanstone Member
Pittsburgh coal seam "No. 8 Coal"

|

Kasimovian|

Conemaugh Group

Casselman Formation

*     Upper Pittsburgh Limestone Member
Little Pittsburgh coal seam
Lower Pittsburgh Limestone Member
Connellsville Member
Morgantown Member
Birmingham Member

Glenshaw Formation

*     Ames Limestone
Pittsburgh Red Beds
Upper Bakerstown coal
Upper Saltsburg Sandstone Member
Woods Run Limestone Member
Lower Saltsburg Sandstone Member
Pine Creek Limestone Member
Buffalo Sandstone Member
Bush Creek Limestone Member

Mahoning Formation

*     Bush Creek Coal
Upper Mahoning Sandstone Member
Mahoning Coal "No. 7a Coal"
Lower Mahoning Sandstone Member

Moscovian|

Allegheny Group

Freeport Formation

*     Upper Freeport Coal "No. 7 Coal"
Upper Freeport Limestone Member
Butler Sandstone Member
Lower Freeport Coal "No. 6a Coal"
Upper Freeport Limestone Member
Freeport Sandstone Member

Kittanning Formation

*     Upper Kittanning Coal
Johnstone Limestone Member
Middle Kittanning Coal "No. 6 Coal"
Lower Kittanning Coal "No. 5 Coal"
Kittanning Sandstone Member

Clarian Formation

*     Clarian Coal "No. 4a Coal"
Vanport Limestone Member
Brookville Coal "No. 4 Coal"
Brookville Member

Pottsville Group

Beaver River Formation

*     Homewood Sandstone Member "1st Salt Sand"

Mercer Formation

*     Upper Mercer Limestone Member
Upper Mercer Coal
Lower Mercer Limestone Member
Lower Mercer Coal "No. 3 Coal"

Bashkirian|

Pottsville Group

Connoquenessing Formation

*     Upper Connoquenessing Sandstone Member "2nd Salt Sand"
Quakertown Coal "No. 2 Coal"
Quakertown Fire Clay
Quakertown Shale
Lower Connoquenessing Sandstone Member

Sharon Formation

*     Sharon Shale Member
Sharon Coal "No. 1 Coal"
Sharon Sandstone

| Serpukhovian|

* Shenango Formation

Mauch Chunk Group

*     Bluestone Formation
Princeton Formation
Hinton Formation
Maxton Sandstone
Bluefield Formation "Little Lime"

|

Viséan|

* Greenbrier Limestone "Big Lime" Loyalhanna Formation

Tournaisian|

* Cuyahoga Formation

Pocono Group

*     Burgoon Formation "Big Injun Sandstone"
Sunbury Shale
Berea Sandstone
Bedford Shale
* Rockwell Formation

| Upper|

| Famennian|

* Brallier Formation
* Lock Haven Formation
* Riceville Formation
* Oswayo Formation
* Bedford Shale
* Cussewago Formation

Venango Group

*     Gantz, Hundred-foot sand, Fifty-foot sand, Thirty-foot sand, Nineveh-Snee, Gordon Stray, Fourth Sand, Fifth Sand, Bayard Sand, Elizabeth Sand, Sweet Richard,
Chadakoin Formation, First Warren

Bradford Group

*     Upper Warren, Lower Warren, Speechely Stray, Speechely, Balltown A, Balltown B, Balltown C, Sheffield, First Bradford, Second Bradford, Third Bradford, Kane

Elk Group

*     1st Elk Sand, 2nd Elk Sand, 3rd Elk Sand, 4th Elk Sand, 5th Elk Sand

Ohio Shale

*     Cleveland Shale
Chagrin Formation
Huron Shale

* Java Formation
* Rockwell Formation
* Huntley Mountain Formation
* Hampshire Formation

Catskill Group

*     Duncannon Member
Sherman Creek Member
Irish Valley Member

|

Frasnian|

Catskill Group

*     Sherman Creek Member
Irish Valley Member

* Brallier Formation
* Lock Haven Formation

West Falls Group

*     Angola Formation
Rhinestreet Shale

Sonyea Group

*     Cashaqua Shale
Middlesex Shale

Genesee Group / Harrell Shale

*     West River Shale
Penn Yan Formation
Burket Shale / Geneseo Shale

* Knapp Conglomerate
* Murrysville Sandstone

Middle|

| Givetian|

Tully Limestone

Hamilton Group

*     Moscow Formation
Ludlow Formation
Skaneateles Formation
Tichnor Formation
* Mahantango Formation

|

Eifelian|

Hamilton Group

*     Marcellus Formation

Onondaga Limestone

*     Seneca
Moorehouse
Nedrow
Edgecliff

* Huntersville Chert

*     Bobs Ridge Sandstone Member
* Needmore Shale

Lower|

| Emsian|

Huntersville Chert, Needmore Shale, Bois Blanc Formation
Oriskany Formation
Helderberg Group (geology)

|

Pragian|

Helderberg Group (geology)

Lochkovian|

Helderberg Group (geology)

*     Keyser Formation
Manlius Limestone

| Pridoli|

* Bass Islands Formation
* Akron Formation

Salina Group

*     Bertie Formation

|

Ludlow|

| Ludfordian|

Salina Group

*     Camillus Formation

|

Gorstian|

Salina Group

*     Syracuse Formation

Wenlock|

| Homerian|

Salina Group

*     Vernon Formation

Lockport Group

*     Guelph Formation
Eramosa Formation
Goat Island Formation
Gasport Formation

|

Llandovery|

Clinton Group

*     Rochester Shale
Rose Hill Formation "Red Clinton"

Medina Group

*     Tuscarora Formation

| Upper|

* Queenston Formation
* Reedsville Formation
* Utica Shale

Trenton Limestone Group

Black River Group

Loyalsburg Formation

|

Middle|

* Wells Creek Formation

* Knox Supergroup
* Beekmantown Group:

*     Bellefonte Formation

Lower|

Knox Supergroup

Beekmantown Group

*     Axeman Formation
Nittany Formation
Stonehenge Formation

| Furongian|

* Knox Supergroup

* Gatesburgh Formation
* Warrior Formation

|

Series 2|

| Stage 4|

* Kinzers Formation

|

* Potsdam Formation
* Pleasant Hill Formation
* Waynesboro Formation
* Tomstown Formation
* Antietam Formation

pЄ|

* Grenville Complex

* v
* t
* e

Chronostratigraphy of West Virginia

Ph|

| Cz|

| Pe|

| Eocene|

Igneous intrusives

|

Mz|

| J|

Igneous intrusives

|

Pz|

| P|

| Cisuralian|

| Asselian|

* Dunkard Group

|

| ⁋|

| Gzhelian|

* Monongahela Formation

|

Kasimovian|

* Conemaugh Group

Moscovian|

* Allegheny Formation

Bashkirian|

* Pottsville Group
* Kanawha Formation
* New River Formation
* Pocahontas Formation

| Serpukhovian|

* Bluestone Formation
* Princeton Sandstone
* Hinton Formation
* Bluefield Formation

|

Viséan|

* Greenbrier Group

Tournaisian|

* Price Formation
* Cuyahoga Formation
* Maccrady Formation
* Sunbury Shale
* Berea Sandstone

| Upper|

| Famennian|

* Price Formation
* Berea Sandstone
* Bedford Shale
* Ohio Shale
* Brallier Formation

|

Frasnian|

* Brallier Formation
* Java Formation
* West Falls Formation
* Rhinestreet
* Sonyea Formation
* Harrell Shale
* Genesee Formation

Middle|

| Givetian|

* Tully Limestone
* Hamilton Group

|

Eifelian|

* Hamilton Group
* Marcellus Shale
* Onondaga Limestone
* Needmore Shale
* Huntersville Chert

Lower|

| Emsian|

* Needmore Shale
* Huntersville Chert

|

Pragian|

* Oriskany Sandstone

Lochkovian|

* Helderberg Group

| Pridoli|

* Bertie Formation
* Bass Islands Formation
* Keyser Formation

|

Ludlow|

| Ludfordian|

* Salina Group
* Tonoloway Formation

|

Gorstian|

* Salina Group

Wenlock|

| Homerian|

* Salina Group
* Wills Creek Formation
* Williamsport Formation
* McKenzie Formation

|

Sheinwoodian|

* Lockport Dolomite
* McKenzie Formation

Llandovery|

| Telychian|

* Lockport Dolomite
* McKenzie Formation
* Keefer Formation
* Rose Hill Formation
* Rochester Shale

|

Aeronian|

* Tuscarora Sandstone
* Clinton Sandstone

| Upper|

| Hirnantian|

* Cincinnati Group
* Juniata Formation

|

Katian|

* Cincinnati Group
* Juniata Formation
* Reedsville Formation
* Utica Shale

Sandbian|

* Lexington Limestone
* Trenton Limestone

* Dolly Ridge Formation
* Martinsburg Formation
* Nealmont Limestone
* Oswego Formation

Middle|

| Darriwilian|

* Trenton Limestone
* Black River Group

|

Dapingian|

* St. Paul Group

* St. Peter Sandstone

Lower|

| Tremadocian|

* Wells Creek Formation

Knox Group

* Beekmantown Dolomite
* Rose Run Sandstone

|

| Furongian|

| Stage 10|

Knox Group

* Copper Ridge Dolomite

|

Chilhowee Group
Antietam Formation
Harpers Formation
Weverton Formation
Loudoun Formation

* Conasauga Group
* Conococheague Formation
* Elbrook Formation
* Rome Group
* Tomstown Dolomite
* Waynesboro Formation

pЄ|

| ♇|

| Z|

| Ediacaran|

* Catoctin Formation

|

* Swift Run Formation
* Grenville Complex

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