Carl B. Rexroad

Conodont paleontology of the Providence Limestone Member of the Dugger Formation (Pennsylvanian, Desmoinesian) in the southern part of the Illinois Basin

ABsTRAcr-The Providence Limestone member of the Dugger Formation in Indiana and its lithologic correlatives in the southern part of the Illinois Basin are thin lime mudstones to packstones lying stratigraphically between the Herrin and Hymera Coal Members of the Dugger Formation and their equivalents. The purposes of the study are to describe and correlate the Providence conodont fauna and to apply biofacies analysis and petrographic study to interpreting the paleoenvironments. Providence conodonts are dominated by representatives of the Idiognathodus-Streptognathodus plexus. Hindeodus is abundant; Neognathodus is common; and Idioprioniodus, Adetognathus, and Diplognathodus are common only in some sections. Aethotaxis is a minor constituent.

Introductory geology for elementary education majors utilizing a constructivist approach

Field Excursions in Earth Science. is designed as a non-prerequisite field-based course for elementary education majors. Classic Canadian Shield and Michigan Basin outcrops and Quaternary features are used to teach those Earth science objectives considered most important for K-8 teachers by the Michigan State Board of Education and by others. We integrated these objectives into five conceptual pathways rather than presenting them as discrete pieces of information. A variety of teaching techniques based on constructivist educational theory are employed, so that pre-service teachers experience active-learning strategies in the context of how science is practiced. Our learning strategies address the cognitive and affective domains and utilize personal experiences in conjunction with pre- and post-experience organizers to allow students to develop individual meanings. We place emphasis on observations and concepts and we encourage students to explain their understanding of concepts verbally and in a variety of written formats. Activities address spatial concepts and map reading; mineral, rock, and fossil identification; formation of rocks; surficial processes and landform development; structural deformation and plate tectonics; and environmental issues. Students keep field notes and have daily projects. They address the pedagogical structure of the course in a daily diary.

The new Mississippian conodont genus Synclydognathus

Following the publication of papers by Bergstrom and Sweet (1966) and Schopf (1966), a gradual shift from the use of discrete element taxonomy to multielement taxonomy has occurred in describing conodonts. Although most workers now apply multielement taxonomy wherever possible, systematics have not been updated for many of the conodont faunas described earlier, and as a result the use of multielement taxonomy still is far from universal.

Conodonts from the Paoli and equivalent formations in the Illinois Basin

The conodont fauna of the Upper Mississippian Paoli and equivalent formations in the outcrop area around the margin of the Illinois Basin is described, on the basis of samples collected from 8 localities in Illinois, Kentucky, and Indiana, which yielded an average of 7 specimens per kilogram of sample. Twenty-six species, including the new species Synprioniodina denticamura, and 13 genera were recognized. There are faunal differences between the lower and upper members of the Paoli, and conodonts are somewhat more abundant in the northern localities. There is no apparent lithofacies control of distribution.

An evaluation of the V. J. Gupta conodont papers

Distortion of the paleontologic literature in most of the 450 papers bearing V. J. Gupta as author or co-author during the past 30 years has been documented by Agarwal and Singh (1981), Talent (1989a, 1989b, 1989c, 1990a, 1990b, 1990c, in press), Talent et al. (1988, 1989, 1990, 1991), Ahluwalia (1989), Bassi (1989, 1990), Brock et al. (1991), and Radhakrishna (1991). Replies to the charges of fabrication and distortion by Gupta (1989, 1990a, 1990b) were futile attempts to distract the reader, rather than to provide information to refute the charges.

A Comprehensive Model for Teaching Writing And Oral Skills in the Geology Curriculum

For more than 30 years, educators have expressed concern about communication deficits of science graduates, but no analysis of the written and oral skills geology graduates need in professional careers has been published. Neither has a comprehensive plan been developed within a geology curriculum to augment communication ability. In order to develop a plan to meet this need, we asked geology graduates of Lake Superior State University to submit examples of writing required by their jobs in industry and government. The resulting large numbers of examples were analyzed. From this information, assignments of increasing complexity were designed to teach written and oral communication skills, based on “real-life” activities, within the geology courses of the four-year sequence. For example, five writing activities would be assigned in Physical Geology I for the fall semester of the freshman year, including a report based on a field exercise and one on rock and mineral identification. Each student would prepare...

Conodont Zones in Salamonie Dolomite and Related Silurian Strata of Southeastern Indiana: ABSTRACT

Conodont zones recognized in the Brassfield Limestone and the Salamonie Dolomite (includes the Osgood and Laurel as members) in southeastern Indiana and adjacent Kentucky generally are comparable with Zone-I, the celloni- and amorphognathoides-Zones, and probably the patula-Zone established by Otto Walliser in the Carnic Alps. Differences in generic composition of the European and Midwestern faunas and apparent range extensions suggest a more complex zonation than that established by Walliser. End_Page 629------------------------------ Although the conodont fauna of the Brassfield Limestone conforms in general with that of Zone-I, it appears to be transitional with the celloni-Zone fauna in southeastern Indiana, where the formation is younger than in its type area in east-central Kentucky. Correlation with the European sections is made more difficult because specimens assigned by Walliser to Icriodina irregularis and considered by him to be indicative of the upper part of Zone-I may in fact belong to Scyphiodus, a genus that is present in beds as young as the lower part of the Clinton Group in Ontario. A new platform-type genus derived from Spathognathodus is first recorded in the upper part of the Brassfield. Above the Brassfield Limestone in its classic concept is another lithologic unit, tentatively assigned to the Brassfield, that has a mixed conodont fauna. The conodonts considered indigenous include Icriodina irregularis, Hadrognathus staurognathoides, Carniodus spp., Spathognathodus celloni, Pterospathodus amorphognathoides, and new species thought to belong high in the celloni-Zone. Overlap of S. celloni and P. amorphognathoides shows extension of the known range of one or both species. The conodonts of this zone are morphologically unstable, but the thinness of the unit and admixed material, including Ordovician specimens, do not allow recognition as yet of precise evolutionary development and zonation. The conodonts in the basal part of the overlying Salamonie Dolomite belong in the amorphognathoides-Zone and include Pterospathodus amorphognathoides and Ozarkodina gaertneri. In Europe the upper terminations of these two species and Carniodus coincide, whereas in the Cincinnati arch area the two extend considerably above the highest level of Carniodus. These facts suggest that an unconformity is present in the Carnic Alps between the amorphognathoides- and patula-Zones. If so, most of the Salamonie above the lower beds that contain Pterospathodus may represent an unrecorded time interval, but it is possible that the absence of Kockella patula reflects provincialism. End_of_Article - Last_Page 630------------