32 T. E. Savage — Relations of the Alexandrian Series. 



These exposures indicate that the Charmahon limestone 

 member described in former papers represents only the lower 

 part of the Edgewood formation at this place, and the fossils 

 in the limestone taken from the excavation show clearly that 

 this horizon is the equivalent of the Cyrene member of the 

 Edgewood limestone as developed near Edgewood and Cyrene 

 in Pike County, Missouri, and near Thebes in Alexander 

 County, Illinois. The succeeding brown, almost barren lime- 

 stone that appears in the middle and upper parts of the quarry 

 exposure corresponds to the Bowling Green member of the 

 Edgewood formation. In the quarry no trace of a sedimentary 

 break appears between the upper more barren brown limestone 

 corresponding to the Bowling Green member and the under- 

 lying more fossiliferous portion of the Edgewood formation. 



While the Bowling Green limestone member of the Edge- 

 wood formation in Illinois and Missouri is almost barren of 

 fossils, careful search in the several good exposures has yielded 

 a few shells of the following species : — Atrypa pramiarginalis, 

 Atrypa putilla, Camarotmchiaf concin?ia, Dalmanella edge- 

 woodensis', Whitfieldella ovoides. 



These are all characteristic Edgewood fossils, not one of 

 which have been found in the Gower or Anamosa limestone 

 or in any other horizon hitherto recognized in the Silurian 

 rocks of Iowa. They clearly link the Bowling Green lime- 

 stone with the Edgewood formation, as was indicated in my 

 paper on the Alexandrian series. 



Stratigraphic relations of the Bowling Green limestone member. 



The close relation of the fowling Green limestone member 

 with the underlying lower portion of the Edgewood formation 

 has been already described. It was shown in my paper on the 

 Alexandrian series that the Bowling Green limestone member 

 of the Edgewood is in many places unconformable overlain by 

 the Sexton Creek limestone of about Brassfield age. The 

 lower layers of the Sexton Creek limestone almost everywhere 

 contain the fossils Pentamerella f manniensis and Pentamerus 

 cf. ovalis, which mark a narrow zone near the base of the 

 formation. In a horizon 18 to 25 feet above the Pentamerella f 

 manniensis zone the following species are abundant: — 

 Phinopora near verrucosa, Strophonella filistriata, Strick- 

 landinia triplesiana, Slricklandinia sp., Triplecia ortoni, and 

 other fossils characteristic of the Brassfield limestone of 

 Indiana, Ohio, and Kentucky. 



In the river bluff between Clarkesville and Kisenger, in 

 Pike County, Missouri, the Bowling Green limestone member 

 is followed unconformably by 9 to 12 feet of gray non- 



