318 Rowley — Edgewood Limestone of Pike County, Mo. 



the oolite farther west, it should have, at the least, some of 

 the oolite fauna, which is here not the case. It is true that 

 spots, so to speak, of oolitic character do occur at the Watson 

 locality, and the writer has slabs of this oolitic brown stone 

 filled with the fossil species peculiar to the Cyrene and McCune 

 beds, but without a single form characteristic of the Noix 

 oolite. Usually there is a break in sedimentation between the 

 oolite and the Cyrene beds and a greater difference between 

 their faunse than between the Cyrene and Bowling Green 

 members ; still, the relationship in genera and allied species of 

 fossils is so close that the three horizons may be regarded as 

 faun ally continuous. 



The Mcllroy locality, about nine miles southeast of Louisiana 

 and four miles northwest of Clarksville, presents the three 

 horizons in the same outcrop. Eight feet of pale blue oolite 

 with its usual coral fauna overlies the blue Ordovician shale 

 (Buffalo), and in turn is overlain by eight feet of hard brown 

 limestone carrying the Cyrene fauna and in addition the corals 

 of the Edgewood locality. Nine or ten feet of a soft, almost 

 clayey limestone with few fossils inclosed in rounded nodules 

 overlies the Cyrene bed and is a local phase of the Bowling 

 Green member. 



It is peculiar that the eight feet of oolite at Mcllroy, with 

 its fauna, should disappear before the Cyrene locality, five 

 miles southwest of Mcllroy, is attained, yet such is the case. 



The oolite has its greatest thickness along the Mississippi 

 river front and thins out rapidly westward, disappearing alto- 

 gether five or six miles west of Louisiana. It therefore 

 follows that where the oolite is thickest, the brown stone is 

 thinnest, and vice versa. 



At Louisiana along the Mississippi river the oolite in two 

 heavy beds attains a thickness of eight feet, while the brown 

 stone is scarcely eighteen inches thick. However, at the mouth 

 of Buffalo creek two miles southeast of Louisiana, in the bluff 

 facing the river, the brown stone is over eight feet thick, 

 while the oolite is a little less. Near the C. & A. H. R. bridge, 

 two and a half miles northeast of Bowling Green, the total 

 thickness of the Silurian beds is quite thirty feet, including 

 the type outcrop of the Bowling Green limestone, and the 

 recently uncovered Cyrene beds below, the former alone hav- 

 ing a depth of over twenty feet. 



Half a mile southwest of Vera or Watson station, in the first 

 cut along the C. & A. R. R., the Cyrene beds are replaced by 

 the Watson horizon which rests on the Ordovician shale and 

 yields an abundance of fossils, but of few species, notably 

 Atrypa prcemargincdis. The Watson bed is either the very 

 base of the Bowling Green limestone, with which it agrees 



