The occurrences of species of Delotaxis and Icriodus and the Ozarkodina remscheidensis eosteinhornensis--Ozarkodina remscheidensis remscheidensis lineage indicate that (1) most of the Keyser Formation of western Virginia is assignable to the uppermost Silurian eosteinhornensis zone; (2) the top of the upper limestone member of the Keyser is assignable to the basal Devonian woschmidti zone; (3) the remainder of the Helderberg Group is no younger than the delta zone; and (4) the basal Needmore Shale at the Price's Bluff section is assignable to the serotinus, patulus, or costatus costatus zones, of uppermost lower Devonian and lowermost Middle Devonian age, leaving a gap of at least six conodont zones represented by the Ridgeley Sandstone and its bounding unconformities. Conodonts tend to avoid tidal flat and lagoonal environments. They are not uniformly distributed through the rest of the section, but the occurrence of all but two species is not related to water depth, energy, or substrate; Ozarkodina excavata and Pseudooneotodus beckmanni prefer moderate energy environments. Icriodus helderbergensis and most of the simple cone species are associated with each other. There were 13,360 specimens collected, divided among 10 biological species and 15 form species; of the biological species, 3 are new and 2 are newly reconstructed apparatuses. / Master of Science

Foraminifera of the Paleocene Aquia Formation outcropping near Hanover, Virginia were studied in terms of their taxonomy, stratigraphic distribution and abundance. A total of seventy-nine species were described, eight of which have never been reported in the Aquia. Twenty species of planktonic foraminifera were recovered. The basal seven feet of Aquia contains only long ranging Paleocene Foraminifera. In the next two feet of Aquia occurred Globigerina triloculinoides and Globorotalia acuta which overlap in the Middle Paleocene Globorotalia pusilla pusilla Zone and the Late Paleocene Globorotalia pseudomenardii Zone. The next section of Aquia, from nine feet above its base to six feet below the overlying Marlboro Clay, is referred to the Globorotalia pseudomenardii Zone based on the occurrence of Globorotalia aequa and Globigerina triloculinoides. The top six feet of the Aquia and basal one foot of Marlboro Clay contain Globorotalia subbotinae and Globorotalia occlusa placing this section in the Late Paleocene Globorotalia velascoensis Zone. The basal Aquia f oraminif eral fauna is characterized by low species diversity, high morphologic variability in dominant species and large populations suggesting an unstable, marginal marine environment. The upper sections of the Aquia Formation contain faunal associations with higher species diversity, lower dominance and smaller populations indicating a somewhat deeper water, more stable environment. The associated macrofossil communities and local lithologies support these conclusions. A cross-section through the study area reveals offsets in formational boundaries and unusual downdip thickening of the Tertiary section. Accompanying these anomalies are abrupt changes in the course of the Pamunkey River. These data suggests faulting in the study area analogous to the faulted Coastal Plain strata near Fredericksburg, Virginia (Mixon and Newell, 1978), / Master of Science

Makurath (1977), in studying the Keyser Limestone, concluded that brachiopods were distributed randomly, casting doubt over the validity of using recurrent communities as a paleoenvironmental tool. However, a re-evaluation of the Keyser fauna, utilizing cluster analysis, polar ordination, and detrended correspondence analysis, reveals that the fauna can be arranged along a gradient, according to distance from the shore. Recurrent communities do exist within the Keyser Limestone. With the aid of coenocorrelation curves, they can be traced along the entire Appalachian basin. The most nearshore community, belonging to Benthic Assemblage 1 of Boucot (1975), is the Stromatolite Community, followed by the Tentaculites-Meristella-Cupularostrumgordoni Schuchertella and Meristella Communities of Benthic Assemblage 2, the Stromatoporoid-Coral, Crinoid, and Gypidula communities of Benthic Assemblage 3, the Dalejina -Atrypa-Rhynchospirina Community of Benthic Assemblage 4, and the Eccentricosta-Cupularostrum Assemblage 5. / M.S.