T. E. Savage — Relations of the Alexandrian Series. 31 



thickness of three feet of oolite (Noix oolite member), suc- 

 ceeded by 9 to 14 feet of brown limestone (Bowling Green 

 limestone member) which is followed unconformably by about 

 25 feet of gray to brown (Sexton Creek) limestone containing 

 Pentamerellaf manniensis in the lower part, and Rhinopora 

 near verrucosa, Strophonella filistriata, StricMandinia trip- 

 lesiana, Triplecia ortoni, and other common Brassiield fossils 

 near the top. The brown (Bowling Green) limestone member 

 in this region furnished a few good shells of Atrypa praemar- 

 ginalis. 



An important addition to our knowledge of the Channahon 

 limestone member, and its relation to the Edgewood formation 

 in southwest Illinois and Pike County, Missouri, and to the 

 Essex limestone in Kankakee County, Illinois, was made during 

 the summer of 1913. This information proves the correctness 

 of the previous correlation of the Channahon limestone, and 

 indicates that sedimentation was continuous in that region from 

 the bottom of the Channahon limestone member of the Edge- 

 wood to the top of the brown limestone corresponding to the 

 Bowling Green member. 



In the south bank of Des Plaines river, two miles south of 

 Channahon and one mile below the exposure of the Channahon 

 limestone previously described, 44 ' strata corresponding to "No. 2 

 of the old section of the Channahon limestone are exposed 

 above 8 feet of bluish (Maquoketa) shale. In making an ex- 

 cavation near this place the rocks from a zone 5 to 7 feet higher 

 than number 2 of the old section were taken out and piled 

 near by. From the stone taken from this excavation the fol- 

 lowing fossils were collected : — ^Lyellia thebesensis, Atrypa 

 prcemarginalis, Atrypa putilla, Camarotoechia? concinna, 

 Dalmanella edgewoodensis, Rhynchotreta thebesensis, Schu- 

 chertella curvistriata, Whitfieldella ovoides, Cyclonema day- 

 tonensis, Dalmanites sp. 



One and one-half miles farther down the river a small quarry 

 has been opened in the south bank, exposing a thickness of 

 about 14: feet of brown limestone, the lower part of which was 

 at about the same level, and represented about the same 

 horizon, as the rocks taken out of the excavation. The lime- 

 stone in the lower part of this quarry contained Lyellia 

 thebesensis, Atrypa putilla, Dalmanella edgeiooodensis, and 

 Whitfieldella ovoides, while that in the middle and upper parts 

 was almost barren, furnishing only a very few shells of Atrypa 

 putilla and Whitfieldella ovoides. A few rods south of this 

 quarry a ledge of gray limestone 9 feet thick, containing char- 

 acteristic Sexton Creek fossils, is exposed at a level about 6 

 feet above the top of the upper brown limestone in the quarry. 

 *Bull. Geol. Soc. America, vol. xxiv, p. 367, 1913. 



