PBDB Collection

Williamson Shale, Rochester, BA4/5 BA5 (Silurian of the United States)

Where: New York (43.0° N, 78.0° W: paleocoordinates 24.6° S, 47.4° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Williamson Shale Formation (Clinton Group), Llandovery (443.4 - 433.4 Ma)

• Listed as Upper Llandovery, C6. Pterospathodus amorphagnathoides conodont biozone; BA4/5 BA5 Monograptid-Strophochonetes community

• formation-level stratigraphic resolution

Environment/lithology: offshore shelf; poorly lithified, bioturbated, pyritic, argillaceous, silty shale and poorly lithified, concretionary, calcareous siliciclastic

• Fossil layers generally associated with thin, sandy tempestites (thus, not life assemblages and with some winnowing). Generally reduced oxygen with occasional intervals of anoxia and normal oxygen levels

• Dark gray to black (and rarely dark greenish gray), fissile to platy, laminated clay to slightly silty shales, with rare pyrite and sparse bioturbation, commonly interbedded with thin-bedded quartz arenites (siltstones and sandstones) and occasional carbonate concretions

Size classes: macrofossils, mesofossils

Preservation: trace, concretion

Primary reference: B.Y. Eckert and C. E. Brett. 1989. Bathymetry and paleoecology of Silurian benthic assemblages, late Llandoverian, New York State. Palaeogeography, Palaeoclimatology, Palaeoecology 74:297-326 [P. Novack-Gottshall/P. Hearn]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 77051: authorized by Phil Novack-Gottshall, entered by Paul Hearn on 18.12.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• BA4/5 BA5 Monograptid-Strophochonetes community; in Eckert and Brett, 1989: BA5 Monograptid-"Chonetes" cornutus association

Show authors, comments, and common names

Demospongiae
Hadromerida - Suberitidae	Chaetetes lycoperdon Chaetetes lycoperdon demosponge "Present, abundance unspecified"
Pterobranchia
Dendroidea - Acanthograptidae	Dictyonema sp. Dictyonema sp. Hall 1851 graptolite "Present, abundance unspecified"
Graptoloidea - Monograptidae	Monograptus clintonensis Monograptus clintonensis graptolite "Very abundant, dominant"
Graptoloidea - Retiolitidae	Retiolites geinitzianus Retiolites geinitzianus Barrande 1850 graptolite "venosus", "present, abundance unspecified"
Gastropoda
Murchisoniina - Murchisoniidae	"Hormotoma subulata" = Murchisonia subulata "Hormotoma subulata" = Murchisonia subulata Conrad 1842 snail "Present, abundance unspecified"
Cephalopoda
Orthocerida - Orthoceratidae	Orthoceras bassleri Orthoceras bassleri "Present, abundance unspecified"
Rhynchonellata
Atrypida - Atrypinidae	Atrypina disparilis Atrypina disparilis Hall 1852 "Present, abundance unspecified"
Atrypida - Atrypidae	Atrypa reticularis Atrypa reticularis Linnaeus 1758 "In some cases very abundant"
Protorthida - Skenidiidae	Skenidioides pyramidalis Skenidioides pyramidalis Twenhofel 1928 "Present, abundance unspecified"
Orthida - Dicoelosiidae	Dicoelosia biloba Dicoelosia biloba Linnaeus 1758 "In some cases very abundant"
Pentamerida - Clorindidae	Clorinda fornicata Clorinda fornicata "Present, abundance unspecified"
Athyridida - Meristellidae	Whitfieldella cf. oblata Whitfieldella cf. oblata "Present, abundance unspecified"
Strophomenata
Orthotetida - Chilidiopsidae	"Coolinia subplana" = Fardenia (Coolinia) "Coolinia subplana" = Fardenia (Coolinia) "Present, abundance unspecified"
Strophomenida - Chonetidae	"Chonetes" cornutus "Chonetes" cornutus "Very abundant, dominant"
Strophomenida - Sowerbyellidae	"Eoplectodonta transversalis" = Eoplectodonta (Eoplectodonta) transversalis "Eoplectodonta transversalis" = Eoplectodonta (Eoplectodonta) transversalis Wahlenberg 1818 "Common"
Ostracoda
Palaeocopida - Beyrichiidae	Beyrichia aff. lakemontensis Beyrichia aff. lakemontensis ostracod "Present, abundance unspecified"
Palaeocopida - Zygobolbidae	Mastigobolbina punctata, Mastigobolbina trilobata, Mastigobolbina typus Mastigobolbina punctata ostracod "Present, abundance unspecified" Mastigobolbina trilobata ostracod "Present, abundance unspecified" Mastigobolbina typus ostracod "Present, abundance unspecified"