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



of the Bowling Green limestone member to the underlying 

 portion of the Edgewood formation in this region indicate the 

 following sequence of events : During early Edgewood time 

 the part of the basin in which the Edgewood strata in Pike 

 County, Missouri, were laid down was deepest towards the 

 west side of the area of distribution of these rocks, and was 

 progressively shallower towards the east margin, along the east 

 side of Pike County, Missouri, and in Pike and Calhoun 

 Counties, Illinois, where conditions were favorable for the 

 formation of oolite. During the progress of early Edgewood 

 sedimentation the sea was gradually contracting towards the 

 west side of the basin, until just previous to the beginning of 

 deposition of the Bowling Green limestone, when the east 

 margin of the sea had receded to a few miles west of Louisiana, 

 Missouri. Bowling Green limestone deposition was initiated 

 by a slight uplift of the region bordering the west side of the 

 Edgewood basin in Pike and Lincoln Counties, Missouri, 

 accompanied by a subsidence of the area east of the line of 

 uplift. Sedimentation was thus uninterrupted in the west part 

 of the basin, but the warping resulted in the overlap of the 

 Bowling Green limestone upon the surface of the oolite farther 

 east where there is an abrupt change in lithology and a short 

 sedimentary hiatus at the base of the Bowling Green member. 

 That the unconformity between the oolite and the brown 

 Bowling Green limestone is not of much time significance is 

 also shown by the fact that the fossils that have been found in 

 the Bowling Green limestone member are all typical Edge- 

 wood species. 



Faunal affinities of the Bowling Green limestone member. 



Near Watson station, about eight miles southwest of 

 Louisiana, the fossils Atrypa prcemarginalis, A. putilla, 

 Camarotoeehia f concinna, and Dalmanella edgewoodensis 

 were collected from the lower part of the Bowling Green 

 limestone, above which no trace of unconformity could be 

 detected. 



In the exposure along the Chicago and Alton railroad, about 

 2-^ miles northeast of Bowling Green, the writer collected a 

 number of shells of Atrypa putilla from the ledge of brown 

 Bowling Green limestone, within which no evidence of uncon- 

 formity was found. 



In the east bank of Daggett's branch and along the river 

 bluff at the west end of Grafton, and along a stream 2J miles 

 farther west, in Jersey County, Illinois, good exposures of the 

 Edgewood and associated strata are presented. The Edgewood 

 formation here rests upon Maquoketa shale, and consists of a 



