THE CHESTER SERIES IN ILIINOIS 297 



that name for the formation by Ub-ich. The Paint Creek is the 

 equivalent of the higher portion, at least, of the Gasper limestone 

 of Kentucky. 



MIDDLE CHESTER GROUP 



In passing from the Lower to the Middle Chester formations, 

 the region of typical and more complete development is found to 

 be in the more southern counties of Illinois, rather than in the 

 Mississippi River counties. As in the case of the Lower Chester, 

 the Middle Chester is constituted of four formations, two siliceous 

 and two calcareous. 



Cypress sandstone. — This is the formation for which Engelmann 

 chose the name Cypress sandstone, from the exposures in the bluffs 

 of Cypress Creek, Union County, but it is not the sandstone for 

 which Ulrich used the same name in the report on "The Lead 

 Zinc and Fluorspar Deposits of Western Kentucky."^ The for- 

 mation is continuously present in the Chester section from Hardin 

 County at the east to Union County at the western extremity of 

 the southern belt of outcrop of the formations. It is a very mas- 

 sive, cliff-forming sandstone, and except where it is interrupted by 

 faulting in Hardin, Pope, and Johnson counties, it forms the upper 

 portion of a nearly continuous escarpment across the state which is 

 a conspicuous topographical feature. The formation is more uni- 

 form in its character throughout its extent in these counties than 

 any other sandstone formation in the Chester series. Some other 

 sandstones are just as massive and make just as conspicuous cliffs 

 in places, but they do not retain such a character throughout for 

 the reason that the massive portions of the other sandstones are 

 much more interrupted, both vertically and horizontally, by thinly 

 bedded and less resistent layers. 



The lithologic character of the Cj^ress is similar to other sand- 

 stones of the series, or at least to certain portions of most of the 

 other sandstones. It is rather fine in texture, yellowish brown in 

 color, with more or less cross-bedding, although certain portions 

 of the formation are conspicuously even-bedded, and in places, 

 especially in the upper portion of the formation, the even beds 



^ Prof. Paper, U.S. Geol. Siirv., No. 36 (1905). 



