RAIN.] 



CARBONIFEROUS ROCKS. 21 



Ulricli estimates the thickness of the foniiatioii in this district at 'M)() 

 to 400 feet: 



D'fstrtbiitioit and relatioiix. — The St. Louis outcrops over a consid- 

 erable area in Hardin Connty. In the vicinity of I licks it surrounds 

 the belt of Tullahonia, and is itself surrounded by the Ste. Genevieve. 

 To the southeast of Hicks it is cut oiT by a fault (PI. IV), whicli 

 brings it into juxtaposition with the Birdsville and the Mansfield 

 sandstones. To the east and beyond the limits of the detailed maps 

 the relations are less certainly known, but faulting seems to have 

 largely determined the boundary lines of its areas of outcrop. 



The limestone covers a considerable area adjacent to. the Ohio River 

 and extending from Cave in Rock to Rosiclare. It extends from the 

 river back to Lead Hill, a maximum distance of 3 miles, and its north 

 boundary is in part at least determined by a fault plane. At Eliza- 

 bethtown the limestone is well displayed in the river bank and may 

 be seen immediately in front of the Rose Hotel. It is exposed at 

 intervals down to the small stream entering the river a quarter of a 

 mile below Orr's landing, where the Ste. Genevieve limestone makes 

 its appearance. The relations of the two are not altogether clear. 

 The rocks along the stream dip toward it on either side, and the pres- 

 ence of barite, fluorspar, and quartz seems to indicate a certain amount 

 of fracturing of the rock. There is, however, no certain evidence of 

 faulting, and the relations may be those of simple conformity. Be- 

 tween this point and Big Creek Bridge (PI. II) there are practically 

 no outcrops. At this point the relations of the St. Louis to the Ste. 

 Genevieve are almost certainly those of faulting, such as quite cer- 

 tainly are the relations of the St. Louis and the Cypress sandstone. 



Name and correlation.— ^t. Louis is a well-known name, long 

 applied to the beds here mapped under it. Engelmann, in his early 

 work in this region, correlated these beds with those exposed and 

 studied at St. Louis, and there are no reasons for questioning his 

 conclusions. 



STE. GENEVIEVE LIMESTONE. 



Character and thickness.— The Ste. Genevieve limestone is in many 

 instances lithologically similar to both the St. Louis limestone below 

 and the Tribune above. It is fine grained, medium bedded, and non- 

 magnesian. Its most common distinguishing characteristic is the 

 presence of massive oolitic beds, which may easily be distinguished 

 from the occasional beds of oolite in the other formations by their 

 thickness, massiveness, and light color. The formation has also an 

 abundant and characteristic fauna which is readily recognized. Am- 

 plexus geniculatus and Platycriiius hunts villi may be mentioned 

 among the most widespread of its characteristic fossils. Mr. TTlrich 



