Fort Cassin, VT, Fort Cassin Formation: Cassinian, Vermont

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Cephalopoda - Ellesmerocerida - Ellesmeroceratidae
Cyrtoceras acinacellum Whitfield 1886
1 specimen
(Cyrtoceras) acinacellum
    = Bassleroceras acinacellum Whitfield 1886
Kröger and Landing 2009
Cephalopoda - Ellesmerocerida - Protocycloceratidae
Cyptendoceras ruedemanni Ulrich and Foerste 1936
Kröger and Landing 2009 2 specimens
Protocycloceras geronticum Ulrich et al. 1944
Kröger and Landing 2009 1 specimen
Protocycloceras whitfieldi Ruedemann 1906
7 specimens
    = Protocycloceras lamarcki Billings 1859
Kröger and Landing 2009
Cephalopoda - Ellesmerocerida - Rudolfoceratidae
Orygoceras cornuoryx (Whitfield 1886)
26 specimens
recombined as Rudolfoceras cornuoryx
Orygoceras cornu-oryx
Cephalopoda - Bassleroceratidae
Cyrtoceras confertissimum Whitfield 1936
2 specimens
(Cyrtoceras) confertissimum
    = Lawrenceoceras confertissimum Whitfield 1886
Kröger and Landing 2009
Lawrenceoceras breve (Ulrich et al. 1944)
Kröger and Landing 2009 1 specimen
Cephalopoda - Cyclostomiceratidae
Cyclostomiceras cassinense (Whitfield 1886)
6 specimens
Cyclostomiceras minimum (Whitfield 1886)
11 specimens
Cephalopoda - Tarphycerida - Tarphyceratidae
Pionoceras vokesi Ulrich et al. 1942
Kröger and Landing 2009 1 specimen
Eurystomites kelloggi (Whitfield 1886)
6 specimens
Eurystomites rotundus Hyatt 1894
3 specimens
    = Eurystomites kelloggi Whitfield 1886
Kröger and Landing 2009
Tarphyceras perkinsi (Whitfield 1897)
2 specimens
Campbelloceras hyatti Ulrich et al. 1942
Kröger and Landing 2009 1 specimen
Eurystomites virginianus Hyatt 1894
    = Campbelloceras virginianus Hyatt 1894
Kröger and Landing 2009
Tarphyceras seelyi (Whitfield 1886)
8 specimens
    = Centrotarphyceras seelyi Whitfield 1886
Kröger and Landing 2009
Tarphyceras champlainense (Whitfield 1886)
    = Centrotarphyceras seelyi Whitfield 1886
Kröger and Landing 2009
Centrotarphyceras subundosum Ulrich et al. 1942
Kröger and Landing 2009 2 specimens
Cephalopoda - Tarphycerida - Trocholitidae
Schroederoceras eatoni (Whitfield 1886)
7 specimens
recombined as Curtoceras eatoni
Schroederoceras cassinense Whitfield 1886
synonym of Curtoceras eatoni
Trocholitoceras walcotti Hyatt 1894
1 specimen
Trocholites internestriatus (Whitfield 1886)
4 specimens
Cephalopoda - Endocerida - Proterocameroceratidae
Cameroceras brainerdi (Whitfield 1886)
10 specimens
    = Proterocameroceras brainerdi Whitfield 1886
Kröger and Landing 2009
Endoceras montrealense (Ruedemann 1906)
3 specimens
    = Proterocameroceras brainerdi Whitfield 1886
Kröger and Landing 2009
Cephalopoda - Bisonocerida - Piloceratidae
Piloceras explanator Whitfield 1886
8 specimens
recombined as Cassinoceras wortheni
Cassinoceras explanator (Billings 1865)
Ulrich et al. 1943
Piloceras wortheni
Cassinoceras grande Ulrich and Foerste 1943
Kröger and Landing 2009 4 specimens
recombined as Expandocassinoceras grande
Cephalopoda - Orthocerida - Baltoceratidae
Cyrtobaltoceras gracile Flower 1964
Kröger and Landing 2009 1 specimen
see common names

Geography
Country:United States State/province:Vermont County:Addison
Coordinates: 44.2° North, 73.2° West (view map)
Paleocoordinates:30.6° South, 61.2° West
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Ordovician
10 m.y. bin:Ordovician 2
Key time interval:Cassinian Conodont zone: Oepikodus communis - Reuterodontus andinus
Age range of interval:478.60000 - 468.10000 m.y. ago
Stratigraphy
Geological group:Beekmantown Formation:Fort Cassin Member:Sciota
Stratigraphic resolution:formation
Lithology and environment
Primary lithology: lithified calcareous,carbonaceous "limestone"
Lithology description: Details of the divisions at each of the localities from which each specimen listed are not given, thus I will give a complete description of lithologies summarized by Ruedemann for the formation at two different localities. “Section of the Beekmantown beds at Valcour in ascending order: A1 is a four foot bed of hard bluish gray, gritty dolomite. Strike, n.30 e.; dip, 5˚ s.e. A2 begins 100 feet north of end of A1. 3 feet. Bluish gray dolomite, with lenses of lighter dolomite; the latter very fossiliferous. A3 exposed about 300 feet north of A2. 6 feet. This division is shaly at the base, compact, gray or black at the middle and shaly and black at the top, the whole weathering yellowish. The gray portion is a mass of fossil fragments derived from crinoids, trilobites, cephalopods, gastropods and brachiopods, and contains small rounded pebbles or concretions. The shaly portion at the top is a valuable depository of cephalopods (nautilicones and orthocerecones). A4 is a mass of rocks exposed for a considerable distance along the shore and consisting of an irregular series of beds or gray brown and bluish blake sandy dolomite with thin intercalations of very fossiliferous limestone. The surfaces of the strata are characteristically marked by an entagled mass of vermiform ridges suggesting fucoids, and by channels, suchas are formed on sandy beaches at low tide. These channels are filled with a bluish gray limestone, contrasting with the sandy rocks and choked with fossils, specially orthoceracones, which lie in the longitudinal direction of the channels. The channels run slightly north of east. Systems of large ripple marks extend over some of the rock surfaces. Thickness not obtained. A5, rock exposed on north side of Sibley point, exposures beginning behind Pacno’s barn, where a dolomite bed 4 ½ feet thick rests upon A4. This is followed by a cross-bedded impure limestone containing numerous cephalopods (nautilicones) and other fossils. A6, 6 feet of a purer, blue limestone, which is irregularly bedded and contains seams of black shale. A7, a heavy bed (7 feet) of blue sandy limestone, weathering yellow, exposed at top of bank, at east end of Sibley point. A8, separated by a concealed interval from A7 and consists of about 25 feet of heavy bluish limestone strata, which weather gray, are barren and contain some geodes. This bed ends at the Valcour dock. Strike n. 40 w.; dip, 15˚ s.w.” “Section at East Shoreham in ascending order: Division A. Dark iron gray magnesian limestone, usually in beds one or two feet in thickness more or less siliceous, in some beds even approaching a sandstone, Fossils none. Thickness 310 feet. Division B. Dove colored limestone, intermingled with light gray dolomite, in massive beds. Fossils: Orthoceras primigenium, Cryptozoön steeli. Thickness 295 feet. Division C. In succession gray, thin bedded, fine grained calciferous sandstone; magnesian limestone in thick beds, weathering drab; sandstones, sometimes pure and firm, but usually calciferous or dolomitic; magnesian limestone like no. 2, frequently containing patches of black chert. Fossils, none, except Scolithos minutus Wing. Thikness 350 feet. Division D. In seccession blue limestone, in beds one or two feet thick, breaking with a flinty fracture; the weathered surface with a rough curdled appearance; drab and brown magnesian limestone; sandy limestone in thin beds; blue limestone in thin bands. Fossils: Ophieta complanata, Maclurea affinis, Lituites eatoni, Asaphus canalis and species of Cryptozoön, Bathyurus, Maclurea, Murchisoni, Orthocera, Cyrtoceras. Thickness 375 feet. Division E. Fine grained magnesian limestone in beds one or two feet in thickness, weathering drab, yellowish or brown. Fossils: Bucania tripla, Murchisonia confuse, Bathyurus extans? var., Primitia seelyi and species of Lingula, Maclurea?, Murchisonia, Orthosceras, Bathyurus, Cheirurus?, and encrinal columns. Thickness 470 feet.” “Since we can do no better than base our future stratigraphic work on the larger lithologic divisions recognized by Brainerd and Seely in the Beekmantown formation at East shore ham Vt. And in the Chazy formation at Chazy village, we refer the fossils obtained at other places than the Valcour shore provisionally to those divisions.”
Environment:shallow subtidal indet. Tectonic setting:passive margin
Taphonomy
Modes of preservation:recrystallized,original aragonite,replaced with calcite
Size of fossils:macrofossils
Preservation of anatomical detail:good
Abundance in sediment:abundant
Spatial resolution:autochthonous
Collection methods and comments
Reason for describing collection:taxonomic analysis
Metadata
Database number:42793
Authorizer:P. Wagner, B. Kröger Enterer:K. Koverman, B. Kröger
Modifier:B. Kröger Research group:marine invertebrate
Created:2004-08-05 11:34:19 Last modified:2017-10-09 07:45:07
Access level:the public Released:2004-08-05 11:34:19
Creative Commons license:CC BY
Reference information

Primary reference:

11371.1% R. Ruedemann. 1906. Cephalopoda of the Beekmantown and Chazy formations of the Champlain Basin. Bulletin of the New York State Museum, Paleontology 14:389-611 [P. Wagner/K. Koverman/M. Uhen]

Secondary references:

30173 B. Kröger and E. Landing. 2009. Cephalopods and Paleoenvironments of the Fort Cassin Formation (Upper Lower Ordovician), eastern New York and adjacent Vermont. Journal of Paleontology 83(5):664-693 [B. Kröger/B. Kröger]
30180 E. O. Ulrich, A. F. Foerste, A. K. Miller and W. M. Furnish. 1942. Ozarkian and Canadian cephalopods, Part I: Nautilicones. Geological Society of America Special Papers 37:1-157 [B. Kröger/B. Kröger/B. Kröger]
13254 E. O. Ulrich, A. F. Foerste, and A.K. Miller. 1943. Ozarkian and Canadian cephalopods. Part II, Brevicones. Geological Society of America Special Papers 49:1-240 [P. Wagner/P. Wagner/M. Uhen]