GEOLOGICAL INTRODUCTION 29 



except locally in some of the uppermost beds, and but a single species of 

 Pentremites, P. cherokeeus Hall, has been collected. 



Palestine formation. The formation succeeding the Menard is arena- 

 ceous throughout in most sections, consisting in part of heavy beds 

 of sandstone suitable for building purposes, and in part of thinly bedded, 

 ripple-marked sandstones or arenaceous shales. Locally, however, more 

 argillaceous shales are well developed in the formation. The formation 

 is present in the higher portion of the bluffs at Chester, and has been 

 quarried at several points for building stone. The buildings of the peni- 

 tentiary at Menard are constructed of this rock. The more sandy facies 

 of the formation are exceedingly well exhibited along some of the tribu- 

 taries of Tindall Creek, in Palestine Township of Randolph County. The 

 thickness of the formation is about 75 feet, and it seems to lie with some 

 degree of unconformity upon the subjacent Menard limestone. The 

 only fossils which have been seen in the formation are fragments of Lepi- 

 dodendron trunks. 



Clore formation. The highest formation in the Chester Group in 

 Randolph County, is a limestone immediately overlying the Palestine 

 sandstone. The greatest thickness actually measured is 30 feet, but it 

 certainly exceeds this thickness in many localities. The transition beds 

 from the underlying sandstone to the Clore limestone, consist of arena- 

 ceous and calcareous shales, with some beds of limestone, occupying, in 

 places, an interval of as much as 25 feet below the more continuous lime- 

 stone strata. The lithologic characters of the limestone beds are vari- 

 able, some being thin bedded and almost shaly, others being similar to the 

 Menard in texture and hardness, but usually darker in color, while 

 others are more granular or crystalline. Some shale beds are included in 

 the formation. 



The Clore limestone caps the summits of the hills upon which the 

 city of Chester is built, and it outcrops in the heads of several of the 

 ravines adjacent to the town. The formation also caps some of the 

 higher hills east and northeast of Chester until it passes beneath the over- 

 lying Pennsylvanian. Typical exposures of it occur in the heads of the 

 ravines along the southwest side of the high ridge, extending from Clore 

 school to the Randolph County farm. The most extensive exposures 

 which have come under observation are in Bremen Township of Randolph 

 County, about two miles northeast of the village of Bremen, where a small 

 anticlinal flexure causes its surface outcrops to spread out on either side 

 of Little Mary's River. 



The fossils of the Clore limestone are locally more conspicuous than 

 those of the Menard. Some of the shaly beds are filled with fossils 

 and are suggestive of certain phases of the Okaw formation, but the asso- 

 ciation of species is different. In those beds resembling the Menard in 

 texture, some of the Menard species are commonly present. 



