PAPERS BY MEMBERS 123 



the Waterloo quadrangle, limestone conglomerate. The forma- 

 tion undoubtedly includes some portion of the "lower sand- 

 stone of the Chester group.'* of Worthen. and it is believed 

 that Ulrich's middle and upper divisions of the Cypress in 

 Kentucky should be referred to the Renault. The thicker 

 bedded sandstone and the arenaceous limestone strata of the 

 formation are conspicuously cross-bedded in almost every lo- 

 cality where they are exposed. In general the sandstones 

 are thin-bedded with shaly partings, passing imperceptably 

 into arenaceous shales. In many localities thin flaggy beds 

 of sandstone are pierced by closely crowded, vertical bur- 

 rows a quarter of an inch or less in diameter which in a 

 weathered condition, occur as more or less complete perfora- 

 tions of the beds. Some of the heavier sandstone layers 

 closely simulate the massive Brewerville. Such beds usually 

 occur, when present, in the higher portion of the formation 

 and rarely or never attain a thickness of over 10 to 20 feet. 

 They may be distinguished from the Brewerville. not only 

 liy their less thickness, but also by the presence of the under- 

 lying shales, often variegated, sometimes by underlying 

 limestone strata, and they usually contain some more or less 

 fragmentary fossils. 



The Renault formation is typically developed in the 

 eastern portion of Renault township in Monroe county, where 

 excellent exposures may be seen in the valleys of the two 

 forks of Horse Creek and their tributaries. Good exposures 

 may also be seen in the stream valleys northeast, east and 

 southeast of \\'aterloo. Towards the western border the 

 formation is composed almost entirely of arenaceous strata. 

 Eastwardly the thickness gradually increases until it attains 

 its maximum of from 80 to 100 feet : the calcareous strata also 

 become more conspicuous towards the east, where important 

 crystalline limestone beds are developed. The variegated 

 shales have a conspicuous development in the basal part of 

 the formation in the region northeast of ^^'aterloo. where an 

 important bed of these sediments. 25 feet or more in thick- 

 ness, is frequently exposed in the valleys of Prairie du Long 

 Creek and its tributaries. Similar, but less extensive beds 

 of the same general character, occur elsewhere in the forma- 

 tion, and they may be expected almost anywhere within the 

 area of outcrop. 



The Renault overlap. In its geographic distribution the 

 Renault formation is much more widespread than the sub- 

 jacent Brewerville. since through much of its area it over- 

 laps the Brewerville along its western border, and rests 

 directly upon the St. Louis or Ste. Genevieve limestone, the 

 actual amount of overlap observed in the Renault quadrangle 

 being at least two miles. The unconformable relations of the 



