Distribution of Specimens
The following-pages contain listings of numbers of specimens per taxon, sample by sample, for each stratigraphie unit. Refer to Table 10 for the presently accepted nomenclature and associations,of these elements.
Each sample is supplemented with a, circle, square or triangle to indicate the adequacy of that sample. Samples designed with circles are adequate in all respects ancf are the only samples from which figured specimens were derived. Squares indicate that the sample is satisfactory for biostratigraphic and (or) paleoecologic analysis, but because preservation of the locality is unlikely, no specimens were selected froof them. Most of the localities in this category are strip mines, and ironically, are the very best localities available to study the marine units in detail. Those samples designated with triangles are the poorest. Most of these are float blocks from strip mine spoil banks or other undesirable sample sites. Not only are no specimens figured from these localities, but little use has been made of them in reaching any of the conclusions expressed herein.
Figures & Tables
“Pennsylvanian rocks exposed in Knox, Peoria, Fulton, and Schuyler Counties in northwestern Illinois include 11 major marine units. The oldest marine unit is late Atokan and the youngest is early Missourian; the remainders are Desmoinesian in age. Each unit has produced at least some conodonts, and the more than 200 samples produced an aggregate total in excess of 160,000 conodont specimens. These can be grouped into not fewer 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. oligonodsus, N. anodus, and Gondolella pulchra are described. Although all marine beds were formed in shallow water, generally near shore, they represent the products of highly diverse environments. Conodont biofacies are sharply differentiated and mirror this diversity. Ecologic controls that effected conodont distribution are believed to have been salinity, energy, pH, and possibly biologic antagonism. Neognathodus is the most useful conodont genus for biostratigraphy in these rocks. Four zones and subzones are based on species of this genus and it has permitted relatively precise interregional correlations. Secondary zonations can be based on other genera that supplement the Neognathodus zonation and assist in identifying units. In decreasing importance these are Gondolella, the Idiognathodus-Streptognathodus plexus, and Diplognathodus.”