438 H. F. Bain — Limestone at Bethany, Missouri. 



Feet. Inches, 



5. Limestone, irregularly water-worn 6 



4. Shale, hard, drab __ 6 



3. Limestone, irregularly bedded _ 8 



2. Shale, calcareous, becoming in places a poor grade 



of lime rock _ _ _ _ . . 2 



1. Limestone in thick to thin ledges _ _ 4 



The limestone is quite fossiliferous, the forms collected 

 including : Productus coslatus, Productus longispinus, Athy- 

 ris subtilita, Spirifer earner ata, Spirifer kentuckensis, Die- 

 lasma bovidens, Derby a crassa, Lopophyllum proliferum and 

 Fusulina cylindriea. This fauna is more abundant than is 

 usually found in the same beds farther north, though no exten- 

 sive collections have been made in the latter region and many 

 of the species collected at De Kalb are known to be present, 

 sparingly at least, in the Madison County outcrops. The 

 marked predominance of the Fusalina cylindriea, which is so 

 striking a characteristic of these beds in Madison County, is 

 not so noticeable at De Kalb. This is probably due as much 

 to the greater abundance at the latter point of the other forms 

 mentioned as to any real decrease in the numbers of the Fusu- 

 lina. It is nevertheless true that the Decatur County outcrops 

 show much closer relations to the rocks as developed at Bethany 

 than to the Winterset section in the earlier advent, or at least 

 culmination, of Fusulina. It is for this reason in part, that 

 the term De Kalb limestone is to be preferred to Fusulina 

 limestone, since neither the presence nor the abundance of the 

 latter form is found to be consonant with a constant strati- 

 graphical horizon. 



The beds below the De Kalb limestone are well developed 

 and show no important variation from the standard sections 

 already given. A point of interest is the persistence of the 

 Myalina horizon, which is found on Grand River west of the 

 town of Decatur only less perfectly developed than at Win- 

 terset.* The exposures in and near Davis City show the 

 Earlham and Winterset limestone especially. The Fragmental 

 limestone is shown but is almost non-fossiliferous, as at Bethany. 

 As seen in Clarke County near Osecola it is also un fossiliferous, 

 and the only abundant collections from this horizon were made 

 in the central Iowa counties. 



No attempt has been made to follow the subdivisions of the 

 Bethany south of its type locality. Their persistence in Iowa 

 however, with certain hurried observations at Kansan City and 

 a study of the reports of the University Geological Survey of 

 Kansas, indicates that a portion of the section at least may be 



* Geology of Decatur County, Iowa Geol. Surv., vol. viii. In press. 



