NEW INSIGHTS INTO THE FAUNA OF THE LATE PRAGIAN AGE GLENERIE FORMATION OF NEW YORK

We continue our study of the Glenerie Formation fauna of southeastern New York. The Glenerie collection studied here was collected (by HRF) from 1980-2024. The diversity is higher than previously known for this interval. This fauna is widespread geographically across the Appalachian Basin (in some parts it is referred to as the Glenerie Limestone), the southern mid-continent of North America, the Great Basin, and even northern Mexico (Chihuahua and Sonora). Some species in this collection can now also be recognized in northern South America (Venezuela and Colombia) and suggest that the southern and eastern margins of Laurentia were very close to northern South America by Early Devonian time.

The Lower Devonian Glenerie Formation (global upper Pragian Stage) is a siliceous, cherty formation part of which dissolves in muriatic and natural acids yielding an exquisite fauna of silicified fossils. Correlative upper Pragian units in New York are the Oriskany Sandstone and Connelly Conglomerate formations, although the thin New York Oriskany apparently is only correlative with upper Glenerie strata. The Glenerie Formation in New York overlies the Wallbridge Unconformity north of Kingston NY, and the Connelly Conglomerate in the vicinity of Kingston and Bloomington, NY. The Glenerie Formation was deposited in marine, subtidal conditions, above normal wave base. It is overlain by deeper water facies of the lower Emsian Stage Esopus Formation. The Glenerie fauna is dominated by brachiopods. Boucot (1975) characterized this as the “Big Shell” Community similar in size to the shells of the Oriskany Sandstone. Especially notable among the brachiopod fauna is the near complete absence of atrypoid and gypidulid brachiopods which are better represented in the underlying Helderberg Group and post-Glenerie strata of the Lower Devonian of eastern North America. Our objectives for future study are: 1. Better taxonomic assessment and photodocumentation, 2. Clear paleobiogeographic implications and, 3. Suggestion of a major climatic cooling for the Glenerie interval.