CLAKK COUNTY. 17 



convexus and joints of Grinoidea. The upper division of this limestone 

 thins out entirely about a mile above the bridge, and passes into a green 

 shale like that by which the limestones are separated. The following- 

 section is seen about one mile above the railroad bridge in the creek 

 bluffs and adjacent hill tops : 



Ft. 



Covered slope, with tumbling masses of Quarry creek limestone 20 



Sandstone, npper part massive, with shaly beds^helow 40 to 50 



Pebbly sandstone 8 to 10 



Green clay shales, with a streak of coaly matter 21 



Limestone, upper division of Livingston bed 3 to 



Green shale 3 to 5 



limestone (partial exposure) 3 



The tumbling masses of limestone that are found iu the hilltops 

 hereaway, no doubt belong to the Quarry creek bed, which is found in 

 partial outcrops not more than half a mile back from the creek, and 

 from 80 to 90 feet above its level. The intervening sandstones and 

 shales which separate these limestones in the north-eastern part of 

 Clark county are much thinner than where tbey outcrop on Hurricane 

 and Mill creeks, in the southern portion, indicating a general thinning 

 out of the strata below the Quarry creek bed to the northward. Some- 

 times I have been inclined ^to believe that this upper limestone was 

 unconformable to the beds below, and its disappearance beyond Parker 

 prairie to the south-west, where the apparent trend of its outcrop would 

 naturally caTy it, seems to strengthen this conclusion, but the outcrops 

 of the underlaying beds are so partial and widely separated that it is 

 difficult to determine this point satisfactorily. At any rate, the thick- 

 ness of the beds between these limestones north of Livingston does not 

 exceed 75 or 80 feet, while south of Martinsville they are from 125 to 

 150 feet apart, at least, showing that they thin out rapidly to the 

 northward. The upper division of the Livingston limestone can be seen 

 to thin out entirely about a mile north of the railroad bridge north-west 

 of Livingston, and the other division must also disappear before reaching 

 Edgar county, as Prof. Bradley failed to find it there, as will be seen 

 by his report on that county in Vol. IV of these reports. The Quarry 

 creek limestone is undoubtedly the same bed described by him as No. 3 

 of his Edgar county section ; and if the Livingston beds extended into 

 that county they would be found not more than 60 to 75 feet below his 

 No. 3. Possibly this lower limestone may be represented there by his 

 No. 11, which is described as a "sandy argillaceous limestone, containing 

 pebbles of black limestone and fragments of fossils," as we have nothing 

 in Clark county that can be correlated with that uuless it is one or both 

 divisions of the Livingston limestones. The distance from his No. 3 

 down to coal No. 7 he makes from 185 to 250 feet, while in Clark county 

 the distance from the limestone on Quarry creek to this coal is from 350 

 to 400 feet. 



