Abstract The purposes of this trip are to assist in interpreting the complexities of Pennsylvanian stratigraphy and sedimentation and to collect representative conodonts. The first stop is the West Franklin Limestone Member of the Shelburn Formation, which represents the Desmoinesian-Missourian boundary and the second is the Atokan Lead Creek Limestone Member of the Mansfield Formation. To help provide a general overview of the somewhat repetitive Pennsylvanian rock sequences in southwestern Indiana, we will visit two coal mines, each displaying several hundred feet of Desmoinesian rocks. We will be able to collect conodonts at all stops except Stop 3.

Abstract Pennsylvanian (Atokan舑early Desmoinesian) parasequences in Indiana are thin (2舑13 m; 5舑40 ft) intervals that are composed of coal, siliciclastic, and carbonate-clastic units bounded by paleosols. Because the parasequences exhibit significant lateral and vertical lithologic variability and are so thin, they are difficult or impossible to discern on standard oil and gas geophysical logs. Therefore, in Indiana, regional correlations of this interval based primarily on geophysical logs and lithologic strip logs created from drill cuttings remain controversial. Detailed analyses of proprietary core from numerous locations in Daviess County in southwestern Indiana reveal that the most traceable of the parasequence facies in core are the paleosols which represent exposure surfaces that developed, in most cases, during apparent basinwide drops in relative sea level. Correlations are substantiated by detailed palynologic analyses of material collected from the bases of overlying marine-influenced flooding surfaces and by the use of thin, nearly continuous marker beds and the presence of certain biostratigraphically significant conodonts. Transgressive and regressive facies above the exposure surfaces are preserved with varying significance. The relative significance of the transgressive-regressive facies in a parasequence is, in part, related to the relative rates of changes in accommodation space and sea level. Detailed analyses of coal lithotypes and maceral compositions in two Atokan coal seams reveal that base-level rises during paleomire development were gradual in one and abrupt (catastrophic?) in another. Abrupt transgressions and the preservation of relatively thick transgressive sequences above the exposure surfaces were perhaps related to rates of mire collapse and compaction of the underlying peat (now coal) and soil (paleosol).

Abstract The Falls of the Ohio River is internationally renowned for the profusion of corals and other fossils found in the Devonian beds at this site. Indeed, the earliest paper on its corals was published in Belgium by Rafinesque and Clifford in 1820. Subsequently, about 75 papers have described some 600 fossil species fromthe falls, Other studies have addressed the geomorphology of the area, including in particular the origin and history of the Ohio River and of the falls. The Falls of the Ohio is also important in understanding the Devonian history of southern Indiana and adjacent Kentucky. In reality a series of rapids, the Falls ofthe Ohio encompassed a stretch of the Ohio River about 2 mi (3.2 km) long between Louisville, Kentucky, onthe south bank of the river, and New Albany, Clarksville, and Jeffersonville, Indiana, on the northern bank (Fig. 1). “In these rapids, the river has a descentof twenty-two and a half feet, … but in no case, has it a perpendicular fall of more than three. At high water, an acceleration of current, not usual to other parts of the river, is all that is perceived; but at low water, it cannot be passed by loaded boats, without great risk and danger” (Lapham, 1828). Therefore, the Falls Cities owe their initial growth and development to the fact that during times of low water, boats following this major artery of westward expansion either had to off-load and portageor had to wait for high water.

The Pearson product moment coefficient and the Baroni-Urbani-Buser binary similarity coefficient were used to test the relationship between lithofacies and conodont biofacies in the Beaver Bend Limestone in Indiana. This lower Chesterian limestone includes a variety of lithotopes, but no associations were readily recognizable. Possibly this failure resulted from collecting techniques, a factor that we plan to test with further study.

Because of the early paucity of Silurian conodont studies, it is still necessary to establish a comprehensive zonation and provide the sound systematics requisite for zonation of the Silurian System in North America. Current research indicates that the broad outlines of North American zones will closely parallel those defined in the Carnic Alps by Otto Walliser in 1964. In detail, however, modification is required, and the problems of provincialism and migration indicate need for some geographically restricted zones. The oldest Silurian conodont zone recognized in the Midwest, northern Michigan, and Ontario is yet to be named. Above it the limits of the Icriodina irregularis Assemblage Zone have been established in the same area, but provincial differences between the northern and southern areas are recognized. The next overlying zones, the Neospathognathodus celloni and the Pterospathodus amorphog-nathoides-Spathognathodus ranuliformis Assemblage Zones, have been documented in the Midwest and in the Niagara Gorge area. Younger zones have not been established, but a number of guide fossils of Walliser's zones have been recognized. Kockelella has been found in the upper part of the Louisville Limestone and in the Mississinewa Shale Member (Wabash Formation) in Indiana; Spathognathodus sagitta is present in the Lockport Dolomite in the Niagara Gorge and the St. Clair Limestone in Arkansas; Polygnathoides siluricus and Kockelella variabilis are included in the diversified fauna of the Bain-bridge Formation in Missouri and in the Lafferty Limestone in Arkansas; P. siluricus is also present in the Brownsport Formation and Decatur Limestone in Tennessee; Spathognathodus snajdri is found in the Kokomo Limestone Member (Salina Formation) in Indiana and the top of the Lockport Dolomite in New York; Spathog-nathodus eosteinhornensis is present in the Stonehouse Formation in Nova Scotia; and Spathognathodus remscheidensis is reported from the Syracuse Formation and younger Silurian strata in New York and from the upper part of the Decatur Limestone in Tennessee.

More than 20 characteristic conodont faunas have been recognized in North American Mississippian rocks. Although best known in the Mississippi Valley and southwestern Missouri, they are widespread on the continent. Six zones and four subzones in the Kinderhookian Series are based on lineages of Siphonodella and Gnathodus. A succession of primitive gnathodids in the lowermost part of the series— Protognathodus meischneri, P. kockeli and P. kuehni —matches that in the lower part of the Gattendorfia-Stufe in Germany. The occurrence of Gnathodus punctatus in Missouri, Oklahoma and Arkansas identifies the youngest Kinderhookian and protably correlates with the lower part of the German Pericyclus- Stufe, and with the middle part of the Zaphrentis Zone of the British Avonian. Significant differences are found in the ranges of siphonodellid and gnathodid species in western Europe and America. Several species found together abroad are stratigraphically separate in the central United States. Bactrognathus, Pseudopolygnathus, Gnathodus, Taphrognathus, Polygnathus and Doliognathus subdivide the lower Valmeyeran (Osagian) Series where Bactrognathus distortus marks an especially widespread zone. The occurrence of Pseudopolygnathus triangulus pinnatus in the Doliognathus latus fauna, accompanied in some places by Scaliognathus anchoralis , correlates with part of the S. anchoralis Zone in the German Sauerland. The upper Valmeyeran (Meramecian) zones are characterized by Apatognathus, Taphrognathus and Cavusgnathus, but are more generalized than underlying zones. The base of the Chesterian Series is not easily distinguished by conodonts, but the upper limits of Gnathodus bilineatus and G. girtyi in the Mississippi Valley mark the top of the Glen Dean Limestone and may approximate the lowermost Namurian, the base of the European Upper Carboniferous. Streptognathodus unicornis occurs at the top of the type Chesterian and in Nevada ranges to the top of the Gnathodus girtyi simplex Zone, which apparently contains youngest Mississippian rocks.

The lithologic and paleontologic aspects of the Silurian rocks in North America have been analyzed. The faunal study has resulted in recognition that, at least as far as the Northern Hemisphere is concerned, the Silurian faunas are relatively cosmopolitan. This fact permitted use of the British shelly fossil Series and Llandovery Stages and Llandovery through Ludlow graptolite Zones for correlation. The stratigraphic succession of brachiopods in North America has led to the elucidation of several phyletic lineages. These and the time-stratigraphic units have been utilized in constructing a correlation chart of the North American Silurian rocks. Analysis of the distribution of the North American Silurian rocks, their faunas, and their compositional and textural aspects has revealed certain broad patterns. Dolomites are found over the continental interior. They are rimmed by limestones. The limestones grade outward into fine-grained terrigenous deposits which grade, in turn, to coarser-grained terrigenous materials. The consideration of these broad patterns of rock type distribution has led to the conclusion that the continental interior was covered during much of Silurian time by marine waters. This conclusion poses the problem of finding sources for the terrigenous debris of the same age which rims the vast expanse of carbonates. Satisfactory sources for much of this debris have not been recognized but are inferred to be potentially present around the continental margins. The broad expanse of Early Paleozoic carbonates covering much of the continental interior suggests that later areas of geo-synclinal deposition and orogenic activity situated upon the carbonates were controlled by differential vertical movements.