20 THE DEVONIAN OF MISSOURI. 



few places in the western part of the county and occurs as 

 float in several places, one of which is as far east as 10 miles 

 south of Warrenton. As the horizon of the Mineola is usually 

 weathered to slopes the formation may be present over larger 

 areas, but outcrops showing Mississippian and Ordovician, or 

 Callaway and Ordovician, in contact are not uncommon, and 

 Mineola must be exceedingly limited. 



The writer has not seen outcrops of the Mineola in St. 

 Charles County, but a few fragments of rock from the formation 

 have been sent to him from the western part of the county. It 

 must occur only in patches of small extent and only a few of 

 the patches. 



In northeastern Lincoln County a few patches of small 

 extent are known. In Ralls County, mar Spalding, outcrops 

 are numerous though they do not cover large areas. The greatest 

 thickness examined, about 50 feet, occurs in this locality. Near 

 Rensselaer the crinoidal phase is prominent and crinoid heads 

 are fairly well preserved in considerable numbers. In the northern 

 part of Ralls County the Mineola rests disconformably on the 

 Cooper with a well-developed erosion surface between. Gilbert 

 P. Moore measured and described the following section near 

 Spalding. 



Mantle rock 2 to 10 feet 



Mineola: 



Red fossiliferous sandstone 8 to 20 feet 



Sandy yellow massive-bedded non -fossiliferous limestone 8 to 10 feet 



Red sandstone. . 2 feet 



White cross-bedded very fossiliferous limestone 2 feet 



Hard blue dense limestone 20 feet 



The sandstone is very patchy. In another section about 3 

 miles north of Spalding at the large outcrop near Rensselaer, 

 Moore measured the following: 



Mantle rock 2 feet 



Mineola : 



White limestone composed dominantly of corals and bryozoans 10 feet 



White limestone having a great many fossils other than corals 4 feet 



Brown limestone carrying crinoids in abundance 2 feet 



Very hard brown limestone with few fossils 4 feet 



Hard blue limestone 30 feet 



The thick sections of limestone, much the same from one 

 township to another, indicate the original extent of the forma- 

 tion. The remnants covered by the Mississippian seas were of 

 very limited extent and the upper Devonian seas did not extend 

 into Ralls County. 



In a bulletin of the Geology of Missouri the writer placed the 

 southern boundary south of the Missouri River but later investi- 



