GLEN DEAN CONODONTS 



11 



L0C.4- VIENNA SOUTH 



Shale, buff, sandy, micaceous. 6 



Limestone, gray, brown and red 

 sandy and sholey, fossil. 9' 



Limestone, ligtit to dork gray, 

 medium to coarse-grained, 

 port crinoidal, part oolitic, 

 variable laterally. 

 Contact with Hardinsburg 

 shale approximately 3' below 

 base of this section. 26' 



o 



Fig. 5. — Vienna South, locality 4. Abandoned quarry, 

 west side of Highway 45, about 1.4 miles south 

 of junction of Highways 45 and 165 in Vienna, 

 SE14 SEi/4 sec. 8, T. 13 S., R. 3 E., Vienna quad- 

 rangle, Johnson County, Illinois. 



These are Hibhardella milleri, H. ortha, 

 Lamhdagnathus jragilidens, Lonchodina 

 furnishi, L. paraclaviger , Roundya costata, 

 and Ozarkodina curvata. 



Abundance of the Fauna 



Conodonts are found in at least moderate 

 abundance at all the outcrops sampled (50 

 to 150 specimens per 1000 grams of raw 

 sample is considered abundant). Alto- 

 gether more than 4000 specimens were ex- 

 amined and hundreds of representatives of 

 many species were studied. Conodonts were 

 found to be much more abundant in lime- 

 stone than in shale. 



The most abundant species encountered 

 were Neoprioniodus scitulus and Cavus- 

 gnathus unicornis but they were closely fol- 

 lowed in numbers by Ligonodina obunca 

 and Spathognathodiis cr is tula. Among 

 those also considered abundant are Cavus- 

 gnathus convexa, Ozarkodina compressa, 

 and Spathognathodus spiculus. 



With the exception of eight rare species, 

 all others listed in table 1 occur commonly, 

 but Cavusgnathus cristata, Gnathodus mo- 

 docensis, Hibhardella milleri, Ligonodina 

 hamata, and Neoprioniodus varians were 

 found in slightly larger numbers than the 

 others. Kladognathus prima, Lambdagna- 

 thus jragilidens, and Lonchodina paraclavi- 



LOC. 5 -HARRIS CREEK 



Limestone, gray, coarse-grained, 

 cnnoidal, weathers to thin 

 tan beds 19' 



Covered interval 6 6 



Limestone, dark gray, 

 medium to coarse- 

 grained, crinoidal I4'8" 



ER 



Fig. 6. — Harris Creek, locality 5. Hillside above 

 and below abandoned section of road, NW14 

 NWi^ sec. 15, T. 11 S., R. 9 E., Shawneetown 

 quadrangle, Hardin County, Illinois. 



ger are very uncommon in the Glen Dean; 

 Gnathodus ? sp., Kladognathus mehli, Lon- 

 chodina furnishi, L. cf. L. paraclarki, 

 Roundya costata, Spathognathodus camp- 

 belli, S. cf. S. commutatus, and Trichono- 

 della imperfecta are considered rare. 



Stratigraphic Implications of the 

 Fauna 



Although the 1957 report established the 

 general nature of the conodont fauna of the 

 Chester Series, only one complete sequence 

 was studied and the stratigraphic ranges 

 for species were not well established. Con- 

 sequently, a project to determine precisely 

 the ranges of species in the Chester Series 

 is now in progress. 



The present study was designed to deter- 

 mine the constancy of a conodont fauna in 

 differing lithologies and over wide dis- 

 tances. However, it has developed impor- 

 tant information about stratigraphic ranges. 

 The lower Chester (Renault and Paint 

 Creek) collections studied in 1957 by Rex- 

 road were large enough (200 or more speci- 

 mens) to be considered truly representative. 

 Comparison of these faunas with those of 

 the middle Chester Glen Dean indicates 

 that several forms, Cavusgnathus characta, 

 Ozarkodina recta, O. ? bella, and Neopri- 



