. Early Llandovery crinoids and stelleroids from the Cataract Group (Lower Silurian) in southern Ontario, Canada . Text-fig. 1 Locality map of southwestern Ontario and western New York State showing occurrences (x) of echinoderms in the Cataract Group. Twelve Mile Creek. Brower (1966) described Calceocri- nus pustulosus from the Manitoulin Formation at Stoney Creek. Brett (1978a) described Ptychocrinus medinensis from the lower Medina Group in the Niagara Gorge near Lewiston in New York State. Materials and Methods A complete section of the Cabot Head Formation is exposed in the gorge below th

- Image ID: MAATP1
. Early Llandovery crinoids and stelleroids from the Cataract Group (Lower Silurian) in southern Ontario, Canada . Text-fig. 1 Locality map of southwestern Ontario and western New York State showing occurrences (x) of echinoderms in the Cataract Group. Twelve Mile Creek. Brower (1966) described Calceocri- nus pustulosus from the Manitoulin Formation at Stoney Creek. Brett (1978a) described Ptychocrinus medinensis from the lower Medina Group in the Niagara Gorge near Lewiston in New York State. Materials and Methods A complete section of the Cabot Head Formation is exposed in the gorge below th
The Bookworm Collection / Alamy Stock Photo
Image ID: MAATP1
. Early Llandovery crinoids and stelleroids from the Cataract Group (Lower Silurian) in southern Ontario, Canada . Text-fig. 1 Locality map of southwestern Ontario and western New York State showing occurrences (x) of echinoderms in the Cataract Group. Twelve Mile Creek. Brower (1966) described Calceocri- nus pustulosus from the Manitoulin Formation at Stoney Creek. Brett (1978a) described Ptychocrinus medinensis from the lower Medina Group in the Niagara Gorge near Lewiston in New York State. Materials and Methods A complete section of the Cabot Head Formation is exposed in the gorge below the lower falls at Ball's Falls on Twenty Mile Creek, near Jordan, Ontario, 25 km west of Niagara Falls (Text-fig. 1). Most of the material that forms the basis of this report was collected from this locality during May 1977 and April 1978. Collecting was most productive at those times since the stream had scoured and cleared the outcrop of talus and other debris, rendering visible crinoid ossicles that would otherwise have been overlooked. Most specimens were recovered through excavation of favourable areas. The precise horizon of each occurrence was determined using a hand-held level. The scrubbing of slabs in the field with a toothbrush revealed many

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