452 JOSIAH BRIDGE AND B. E. CHARLES 



(Fig. 2). It occupies a little knoll between two gullies, and when 

 first found consisted of a number of knobs of quartzite projecting 

 from the hill and having a rough ahgnment. The base was con- 

 cealed, but just above the top of the outher were a number of 

 Mississippian bowlders, and on the north, west, and south at higher 

 and lower levels are outcrops of the Jefferson City formation^ 

 (Fig. 2). 



The summit of the ridge is capped by a thin stratum of Penn- 

 sylvanian sandstone, and bowlders of Pennsylvanian float are found 

 in abundance at lower levels. The Pennsylvanian rests uncon- 

 formably upon the Jefferson City formation on the east side of the 

 hill. On the west side there appears to be a thin stratum of Missis- 

 sippian between them, but the exposures are very poor, and the 

 exact relationships are difficult to determine. The areal distribu- 

 tion of these rocks is shown on the map^ (Fig. 2). 



An excavation was made along the side of these quartzite 

 masses in an attempt to expose the lower contact. This was not 

 entirely successful, but the excavation showed that there was a 

 continuous ledge of quartzite at least thirty feet long and from 

 three to six feet in thickness, increasing in thickness toward the 

 east. Beyond the limits of the excavation there are a few other 

 knobs of quartzite, probably continuous with the part just 

 described. This makes the total length of the outlier about fifty 

 feet, and its greatest width slightly less. It is entirely confined 

 to the Httle nose between the two gullies, and none has been found 

 on neighboring hillsides. Bedding is indistinct, but there are 

 indications of an eastward dip of about 15°. This is regarded as 



^ The Jefferson City beds exposed on this hillside are among the youngest known 

 in this area. They consist of yeUow earthy dolomites (cotton rock) interbedded with 

 chert layers, which are often abundantly fossiHferous, a condition not observed in the 

 lower beds of the same formation in the RoUa area. The fossils consist entirely of 

 one or two species of Hormotoma, closely allied to H. artemesia. It is quite probable 

 that these upper beds belong to the Cotter formation, which overlies the Jefferson 

 City in the southern portion of the uplift, but which has not been recognized in this 

 area. This cannot be definitely stated, however, until the Cotter and its contained 

 fauna are more completely described. 



2 The writers are greatly indebted to Major C. E. Cooke, professor of topographical 

 engineering in the department of vocational education, and his students, Messrs. 

 Kimball and Hazlewood for making the topographic base for this map. 



