Middle to upper Lower Devonian strata in New York are comprised of seven formations, in four distinct vertical packages. They were deposited over an interval of approximately 18.2 million years. The lowest strata (lower Pragian-age Port Jervis Limestone) occur only in the Tristates area, southeastern New York. Overlying upper Pragian-age units are the largely co-eval Oriskany Sandstone, Glenerie Cherty Limestone, and Connelly Conglomerate. Overlying synorogenic siliciclastics of the Esopus Formation (lower Emsian-age) are restricted to eastern to east-central New York. Overlying upper Emsian strata of the correlative Schoharie and Bois Blanc formations comprise mixed siliciclastic-carbonate and carbonate strata, respectively, with some quartz arenites, especially across central New York. These New York units, and their correlatives across the Appalachian Basin outcrop belt, areexamined and summarized.

In nearly all of New York, some to all of these strata are absent at an erosional unconformity. The Tristates area at the meeting of New York, New Jersey, and Pennsylvania is the only area of the outcrop belt where deposition was continuous through this time. To the overall north and west, a major Paleozoic sea level lowstand \r A crustal flexure during the Acadian orogeny led to development of an amalgamated series of unconformities, focused around the sub-Oriskany Wallbridge Unconformity. Maximum development of the unconformity in New York occurs in the west-central part of the state. In terms of sequence stratigraphy, the entire succession comprises six or seven major, third-order sequences. This includes two likely Pragian sequences, and five distinct Emsian-age sequences, all of which appear to be global. A series of altered airfall volcanic tephras occur in the lower part of the Esopus Formation; a few additional discrete airfall tephras are known from the Schoharie Formation. Faunal differences distinguish the four vertical packages of strata. Too little biostratigraphic data, however, continues to limit the accuracy of pinpointing stage boundaries in the New York and Appalachian Basin strata.