•214 



Stol)0 liuiestone. lens— 



fu-et. 



5. Hard, rough, gray, criiioiclal limestone 1 



(i. Hard, gray limestone, few fossils 1-^ 



7. Hard, gray limestone with rusty particles and crinoid stems 5 



S. Soft, blue, sandy shale ^"^^ 



,,, , , 151 



I otal 



STRATIGRAPHY. 



The Knobstone is the surface rock over the greater part of the region 

 here considered. It extends from Brown County west to the Harrodsburg 

 limestone contact which extends in a general northwest and southeast 

 direction, crossing the country east of Bloomington. Northeast of this 

 line, ho^-ever, there are several detached patches of limestone resting on 

 the Knobstone. The entire thickness of the Knobstone is not exposed 

 in this area; but according to Mr. Siebenthal it is about GOO feet. The 

 formation, as far as examined, is composed of a series of alternating, 

 friable, arenaceous shales and sandstones. On the whole the formation 

 is non-fossiliferous. At intervals, however, as at Stobo Post Office, there 

 nre intercalated, lenticular bods of limestone and calcareous septaria with 

 rich faunas. This formation, on account of its incoherent, loosely- 

 cemented, easily-eroded condition, has been cut up into a confused tangle 

 of crooked ridges and deep hollows which trend in all directions. Coa>- 

 mercially the Knobstone is of little value on account of its friable con- 

 dition, but the arenaceous shales may be of value in the making of In-ick 



and cement. 



The Harrodsburg limestone lies on the Knobstone and below the Salem 

 (Bedford) limestone. In the main, it forms a belt from three to five miles 

 in width along the eastern outcrop of the Salem limestone or oolite, and 

 is bordered on the east by the broken hills of the Knobstone. This lime- 

 stone once covered the entire region east of the oolitic contact, as is 

 attested by its patchy remains in various parts of the county. The triangle 

 between Bean Blossom Creek and White River from Mt. Tabor east to 

 within one mile of Canada Gap is capped with it. A large, irregular, much 

 lobed area of it occurs as the surface rock in the vicinity of the Farr 



