Relative abundances of conodonts stem from abiotic or biotic causes. High frequencies can result from: 1) biotic positive = high standing crop; 2) biotic negative = lethality (mass mortality); 3) abiotic positive = lag concentrates; 4) abiotic negative = starved sedimentation. Neither abiotic cause should substantially affect the taxonomic composition of the fauna, although either biotic cause—good or bad environmental responses—can and must. Pennsylvanian conodont biofacies are clearly established and evidence of their interrelationships and complexity has continued to mount. We currently recognize no fewer than five levels of conodont biofacies: Ia - Primary generic-level biofacies (examples: Cavusgnathus, Aethotaxis) Ib - Secondary generic-level (“nested”) biofacies (examples: Ellisonia with Cavusgnathus, Hindeodus with Aethotaxis) II - Species-level microbiofacies (examples: Idiognathodus delicatus with Missourian Idioprioniodus / Gondolella , Streptognathodus elegantulus with Missourian Aethotaxis ) III - Apparatus-level biofacies (examples: scottognathoid apparatuses least complete with Cavusgnathus, intermediate with Aethotaxis, most with Idioprioniodus in the Missourian) IV - Ecophenotype variant-level biofacies (examples: perhaps two “species” of Ellisonia with contrasting apparatus plans and morphologies in the Desmoinesian, possible Cavusgnathus morphotypes from the Cavusgnathus- to the Streptognathodus -biofacies).

Abstract Pennsylvania rocks exposed in Knox, Peoria, Fulton, and Schuyler Qpunties in northwestern Illinois include 11 major marine units. The oldest marine unit is late Atokan and the youngest is early Missourian; the remainder are Desmoinesian in age. Each unit; has produced at least: some Conodonts, and the more than 300 samples produced an aggregate total in excess of 160,000 conodont specimens. These can be grouped into not fever than 78 kinds, considered species in disjunct element taxonomy. At least 10 multielement genera and 40 multielement species are represented. - Six new species: Diplognathodus illinoisensis, Neognathodus.metanodosus, N. polynodosus, N. oligonodus, N. anodosus and Gondolella pulchra are described. Although ail marine beds were formed in hallow water,generally near shore, they represent the products of highly diverse environments.Conodont biofacies are sharply differentiated ind mirror this diversity. Ecologic.controls that effected conodont distribution are believed to have been salinity,energy, pH and possibly biologic antagonism.

Abstract Pennsylvanian1 rocks form the bedrock surfaqe beneath approximately 75 percent of Illinois. The study area (Fig. 1 next-frame) is generally that northwest of the Illinois River, northeast of the LaMoine Riter, but excludes Henryk Bureau, Stark, and LaSalle Counties/ Included, therefore are Rock island, Mercer, Warren, and Knox Counties (the lower units of vhich were studied by Merrill and King, 1971), plus the present coverjage of the .entire stratigraphie column in Knox, Peoria,.Fulton, and Schuyler Gounties. This study area includes the area covered by Wanless definitive works (1957,1958) on thte Beards town, Glas ford, Havana, and. Vermont quadrangles. Also included Is much of the area covered by the Avon-Canton quadrangle, report (Savage, 1922) and the Peoria quadrangle report (Udden, 1912). Knowledge about this area is therefore relatively detailed, The large surface area covered (roughly 2,650 square miles or 7,000 sq km) presents a great many possible sample sites for the several marine units. The studied marine units that produced conodonts, in descending order (Fig. 2) are the Cramer (Trivoli of literature), Exline, Lonsdale, “Sparland”, Pokeberry, “Sheffield”, Brereton, St. David, Hanover, Oak Grove, Seahorne, “Seville” , and Seville Members. Reasons for the quotations will be explained id the discussions of the units.

Abstract In this study, paleoecologic interpretations have been baaed on regional and local stratigraphy,bed geometry, lithic succession, petrology/petrography, and macro- and microfauna. Stratigraphic and palepecplogic conclusions are strongly interactive. Initial paleoecologic conclusions are strongly interactive. Initial paleoecologic interpretations must employ, among other things the best available stratigraphic information. Once the general paleoecologic framework: becomes established, stratigraphic interpretations can be tested against the environmental picture. For example, if at one locality the eptire thickness of a marine interval is considered to have been deposited under extreme nearshore conditions, it Is not logical to expect the same marine interval to have been, formed under totally nearshore conditions over an extensive geographic area. Conversely, a series of scattered isolated, Iithologically similar outcrops each with a totally nearshore fauna predicts, that the rodcs are not, products of the same marine episode Paleoecologic studies probably overemphasize two factors of ancient environments, water depth and substrate. Depth, is the single most important controlling factor for modern marine Invertebrates as a group, but this importance is lessened considerably if the bathymetric range Involved is compressed from several hundreds of meters to ten meters or so. Many "depth" conclusions in recent paleoecologic literature prove to be energy classifications, relative to wave base (sensu. Rich, 1951a). Substrate, is also probably overemphasized because it Is the one tangible and virtually reproducible aspect of every ancient environment, and the only one that can be observed directly at the present time.

Abstract The youngest unit studied in this area is he Cramer (fomerly Trivoli) Member. Its high stratigraphic position dictates that it will be preserved only on the geographically restricted, topographically high rldgeline running froa Faralngton eastward toward Peoria (Fig. 1 ). Only two Cramer localities within the study area were saapled for conodonts. The two are HLithically dissimilar and not faunally hoaogeneous. The type locality (Wanless, 1957, p. 193) has a aasslve fairly pure limestone and an overlying nodular, argillaceous, packed mixed biomicrite, obviously weathering out of a shale. At locality 3 (Wanless, 1958, locality 169) nodular, pagked Derbya biomicrites alterna te, with shale Interbeds below the aaln limestone member (member 152). The high degrees of lithologic and faunal difference between the two successions may represent distinct stratigraphic units. Faunally, locality 1 is an offshore Aethotaxis -blofacies (1A) to Idioprioniodus -biofacies (IB) unit dominated by platform elements transitional between Idiognathodus and Streptognathodus . Locality 3 is so heavily dominated by elements of the Carusgnathus -biofacies that little else of a diagnostic nature is present. Neither locality has produced unquestioned specimens of Neognathodus or Gondotella . Absence of Neognathodus and domination by Streptognathodus canoellosus are compatible with an early Missourian assignment and suggest its (nearest correlatives to be the Lower Brush Creek .In Ohio and the Bertha in Kansas-Missouri, although aore data are needed for substantiation.. Absences are unsafe criteria for age determinations, and Wanless (1956, p. 50-51) has reported “ Metalonchodina ”, an element that is a component of Idioprioniodus and supposedly restricted to pre-Missourian nocks, to

Abstract Five of the six genera described in the systematics have biostratigraphic usefulness, only Cavusgnathus has shown no potential for zonation, of rocks of this age. For the remaining five, the precision, utility, and reliability vary considerably. Neognathodus has piroved to be the choice for zonation in all particulars. It occurs in nearly all units (all units within its range), it shows a constant distribution of kinds between samples of the same age (no local environmental controls manifest wiitftln the genus), it is common enough to usually provide adequate material from samples jof normal size, and most importantly, it underwent rapid evolution. Work with this enus reinforces the earlier idea (Merrill, 1972b) that its potential is still much greater than its present applications. For example, there is little difficulty in distinguishing neognathodids from Brereton and Oak Gtove localities (provided sufficiently large samples), although these units are presently placed in a single zone/subzone (Table 3). Taken collectively, the Idiognathodus-Streptognathodus plexus provides Some useful biostratigraphic tools. Ultimately it shoudd provide the very best tools for Pennsylvanian biostratigraphy, nevertheless, the overwhelming abundance of idiognathodids that are presently taxondmically indistinguishable reduces their usefulness in most units (Merrill, 1974, p. 21-22). The influx of streptognathodids (S. excelsus in form-taxonomy) in the Spar land and Lonsdale tends to set these units apart. Different streptognathodids (S. oanoellosus) intlte Cramer make that unit readily distinguishable from all others in the study area,. In spite of thkese capabilities, this generic plexus is in a nearly hopeless taxonomic/nomenclatorial muddle. Wors,e