CALLAWAY LIMESTONE. 27 



appears in the first bluff north of Lupus, about half a mile from 

 the railway station. Overlying the sandstone the granular 

 limestone phase, some 6 to 8 feet in thicknesj, caps the bluff. 



Exposures in Boone County. — In the bluffs of the Missouri 

 River in western Boone County the Callaway is extremely 

 patchy and occurs in only a few isolated localities. One of these 

 is about half way between the villages of Providence and Easley 

 where a granular phase bearing large numbers of Atrypa reticu- 

 laris (Linnaeus) fills an old valley in the Cooper. (See Plate 4, 

 figure a.) Railway excavations have left the contact well 

 exposed. At the eastern end of the exposure the Callaway is 

 one inch thick and gradually thickens westward to three feet. 

 Within fifty feet the outcrops are covered with talus and where 

 the horizon reappears less than a quarter of a mile west, no 

 Callaway is present. One mile west of this place the horizon 

 dips under and does not reappear to the northward on the east 

 side of the river. 



South of the outcrop mentioned above the writer has not 

 identified with certainty any outcrop of Callaway for about 

 twenty miles. The Cooper occurs, a few feet thick, and it is 

 impossible to differentiate positively between Cooper and Calla- 

 way owing to the absence of fossils. However, this absence of 

 fossils indicates that the rocks are Cooper. 



Cedar Creek forms the eastern boundary of Boone County 

 and the Callaway is well developed and continuous for about 

 fifteen miles along the creek, ranging up to forty feet in thick- 

 ness. All of its various phases are present from top to bottom. 

 It rests in most places on the Jefferson City with marked non- 

 conformity but in a few places it lies on the St. Peter, where 

 patches of the latter are present. It is succeeded by the Syla- 

 more sandstone, though this cannot be observed in every out- 

 crop, owing to its having a thickness of less than one foot and 

 weathering very readily to a sandy soil. In some places the 

 Chouteau limestone may rest directly on the Callaway. 



Exposures in Callaway County. — From Cedar Creek east- 

 ward through Callaway County the Callaway has its best 

 development and is ordinarily forty to fifty feet thick. The 

 appended list of sections is of typical occurrences. It dips 

 under northward about twenty miles north of the Missouri 

 River in Callaway County, and its northward extent is unknown. 

 A few scattered outcrops in northern Cole County demonstrate, 

 its former extent southward. South of the Missouri River in 



