436 Trans. Acad. Sci. of St. Louis. 



localities in the river bluffs in northern Jefferson County, 

 and is called by Mr. Ulrich the Kimmswick limestone.* 



Thickness from the bottom of the quarry, 55 feet. 



2. Harder, darker colored, brownish or bluish limestone, 

 apparantly somewhat siliceous. Fossils abundant, especially 

 the brachiopod Rhynchotrema caj^ax, which indicates the 

 Kichmond age of the bed. This stratum is apparently con- 

 formable upon the limestone below, but the fossils indicate a 

 much younger age, and when a seriesof sections are examined 

 some distance apart, it is seen to rest upon different beds of 

 the Kimmswick limestone at different localities. The uncon- 

 formity of bed No. 2 upon bed No. 1 is therefore demon- 

 strated both by paleontologic and stratigraphic evidence. f 



Thickness, 1 foot, 6 inches. 



3. Shaly layer of varying characteristics. On the quarry 

 side of the hill this bed is generally yellow in color and is 

 sparingly fossiliferous, the only fossils observed being small 

 pelecypods of upper Ordovician age, specifically identical with 

 forms occuring in the Maquoketa shales in Iowa. In its 

 upper portion this bed has been reworked by the sea in which 

 the superjacent beds were deposited, disturbing its stratifica- 

 tion and occasionally introducing a fossil of the younger beds. 

 In the upper reworked portion of this bed phosphatic nodules 

 occur in orreater or less abundance. The Ordovician asre of 

 this shale is established, however, by the presence of the 

 Maquoketa pelecypods in the undisturbed portion of the bed. 

 On the opposite face of the hill above the railroad cut, this 

 same interval is occupied by a more uniform, brownish, thin 

 bedded, fissile shale, which weathers gray on the outside, and 

 in which no fossils have been seen . 



Thickness, 4 feet. 



4. Light colored, oolitic, fossilferous limestone, containing 

 the fauna described in the present paper. On the quarry side 



* Mo. Bureau Geol nd Mines. Vol. 2, 2nd series, p. 111. 



t The recognition of the relations of these two beds of Ordovician lime- 

 stone, and also of the Maquoketa fauna of the shale bed No. 3, is entirely 

 due to the observations of Mr. Ulrich, although all the points have been 

 confirmed by the writer. 



