MOXROE COUXTY. 273 



found no exposures where accurate measurements of the whole 

 group could be made, but its thickness may be estimated at from I'^i 

 to 300 feet in the southern part of the county, and at something less 

 than 100 feet in the northern part. On sections 9 and 3, in township 2 

 south, range 10 west, we saw the following section above the top of the 

 St, Louis limestone : 



Xo. 1. Bro\rn, ferruginous sandstone 4to 6 feet. 



>"". 2. Green and purple shales, with plates of limestone 6 



Xo. 3. Gray limestone 5 



>~". 4. Ferruginous sandstone 3 



So. 5. Green, blue and yellow shales 15 to 20 



Xo. 6. Ferruginous sandstone and shale 40 to 50 



St. Louis limestone partially exposed. 



At this locality the gray limestone, Xo. 3 of the above section, as 

 well as the plates of limestone intercalated in the shales above it, are 

 filled with the characteristic fossils of this group, among which were 

 Pentremitfs godoni. P. pyriformis, Athyris ambigua, A. Roy'issii, Spwlfer 

 Leidyi, Prodtictus elegans, Archimedes SicaUorana, and numerous plates 

 of Afiaxsizocrinus. Between the sandstone at the base of the foregoing 

 section and the underlaying St. Louis limestone there is about three 

 feet of green and purple shales, with a thin ledge of lime conglomerate 

 intercalated in it. The beds at this point all have a decided dip to the 

 eastward. 



On section 16, township 3 south, range 9 west, about five miles south- 

 east of Waterloo, the lower limestone of the Chester group is partially 

 exposed, on Mr. H. Druse's place, where about six feet of thin-bedded, 

 brownish-gray limestone was found, underlaid by three or four feet of 

 blue clay shale, which directly overlaid the lower sandstone of this 

 group. About a mile north of Mr. Druse's place, on a branch of Prairie 

 du Long creek, the upper portion of the St. Louis limestone is well 

 exposed, forming a perpendicular cliff about twenty feet in hight. Fol- 

 lowing down the creek in an easterly direction for about half a mile, the 

 clip of the beds carries the limestone beneath the surface, and it is 

 immediately succeeded by the sandstone of the Chester series, which 

 forms a perpendicular cliff for some distance along the creek, ranging 

 from forty to fifty feet in hight. 



On a branch of Stone creek, which heads a little to the north-east- 

 ward of Waterloo, the Cuester sandstone is well exposed, the first out- 

 crops appearing about a mile and a half from the town and continuing 

 down the creek for a half mile or more, where about thirty feet in thick- 

 ness of the sandstone maybe seen in the bluffs of the stream. The 

 rock is here partly massive and concretionary in structure, and partly 

 thin-bedded, affording layers from two to four inches in thickness. 

 Proceeding uorth-eastwardly from this sandstone outcrop to the main 



