GLEN DEAN CONODONTS 



15 



The latter, next to Cavusgnathus unicornis, 

 is the most abundant species in the Glen 

 Dean Formation. The megafossils show a 

 similar change in the southern area (No- 

 sow, Swann, personal communications). In 

 many aspects, the conodont faunas of these 

 two southern localities resemble those of 

 the upper conodont zone of the Barnett 

 Formation of Texas and the Delaware 

 Creek Member of the Caney Shale of Okla- 

 homa. 



Conclusions 



The following conclusions are indicated: 



(1) The conodonts in the Glen Dean For- 

 mation are virtually unaffected by changes 

 in lithology and therefore will be useful for 

 correlation between facies; (2) the abun- 

 dance and variety of conodonts in limestone 

 opens an avenue of stratigraphic investiga- 

 tion in many dominantly carbonate sections 

 which have received little attention from 

 conodont workers; (3) conodont faunas are 

 relatively uniform within the Chester Se- 

 ries over broad geographic areas. 



SYSTEMATIC DESCRIPTIONS 



The type and figured specimens de- 

 scribed and illustrated in this paper have 

 been reposited at the Illinois State Geologi- 

 cal Survey. Under the subheading Distri- 

 bution in the discussion of each species, the 

 formations in which it occurs are listed. 

 For detailed information about strati- 

 graphic and geographic distribution of each 

 species see table 1. 



LOG. 12-MULZER BROS. 

 QUARRY 



Siltstone, tan, thin-bedded, stialy. 9' 



Shale, dark gray to black, fissile, 

 silty and micaceous. 25" 



Shale, medium to dark gray, 

 calcareous, silty in upper 

 part, fossiliferous; with 

 irregular thin beds 

 of argillaceous crinoidal 

 limestone, one bed 

 very sandy. 28' 3" 



Limestone, gray, medium 

 to massive-bedded, 

 portly crinoidal, 

 partly oolitic, partly 

 cross- bedded, laterally 

 variable and locolly 

 dolomitic. 23*9" 



ir 



Q_ 



or 



Fig. 12. — Mulzer Brothers Quarry, locality 12. Ap- 

 proximately 2.1 miles N. of junction of Indiana 

 highways 145 and 64, 1,500 feet E. of Highway 

 145, SW14 NEi/4 sec. 10, T. 2 S., R. 2 W., Tas- 

 well quadrangle, Crawford County, Indiana. 



EXPLANATION OF PLATE 4 



All figures X 40 

 Numbers in parentheses after explanations refer to locality and sample numbers, for example 



(12-4) refers to locality 12, sample 4. 



Figure 

 1-3 



4. 5 



6 

 7-10 



11-13 



Ozarkodina curvata Rexroad, n.sp.; 1, inner lateral view of holotype (12-4); 2, outer 

 lateral view of a paratype (12-4); 3, inner lateral view of a paratype (12-4). 

 Lonchodina cf. L. paraclarki Hass; 4, outer lateral view (12-15); 5, inner lateral view 

 (12-composite). 



Trichonodella imperfecta Rexroad; posterior view (13-10). 



Lonchodina paraclaviger Rexroad, n.sp.; 7, inner lateral view of a paratype (12-7); 

 8, outer lateral view of holotype (12-4); 9, aboral view of a paratype (12-composite); 

 10, inner lateral view of a paratype (12-composite). 



Lonchodina furnishi Rexroad, n.sp.; 11, aboral view of a paratype (12-5); 12, inner 

 lateral view of a paratype, a young specimen (13-3); 13, inner lateral view of holo- 

 type (12-3). 



