211 



combined thickness is 9 inches at the south end. On the east face two 

 layers, near the top of the wall, were measured, one of which changed 

 in thickness from 2i/4 to 5 inches in 33 inches, and the other from 2^^ 

 to 51/2 inches in 21 inches. At the northeast corner of the quarry there is 

 5 feet of Louisville limestone about the 6i/^ineh continuous layer, which 

 diminishes in thickness to nothing at the south end. The layers com- 

 posing this 5-foot stratum do not thin gradually, but by an abrupt ending 

 of the several layers. Twenty feet north of the southeast corner is a 

 slight thickening in the upper layer, wliich causes a slight dip north and 

 south. These measurements show that the thickness of some layers in- 

 crease and others decrease with the dip. ' Below the e^i-inch continuous 

 layer the stone is evenly bedded. 



Above the nearly level line of unconformity is fi'om 20 to 48 inches 

 of coarse, sandy-looking limestone in broken layers, with a thin covering 

 of earth above it. Viewed from across the quarry the exposure looks like 

 a broken wall of rubble stone. The results of weathering are very evident, 

 but has not wholly destroyed the lines of continuity, which show in-egular 

 bedding. 



The color of the Louisville limestone changes from blue or blue-gray 

 at the bottom to a gray near the ttncouformity. The overlying layers are 

 veiy nearly l»rown. The upper Lotiisville layers change color gradually, 

 and the freshly broken surface of the brown stone can scarcely be distin- 

 guished from it, btit a marked difference is developed by weathering. 



The quarrymeu allege that the underlying shale is five feet thick, which 

 is very nearly its average thickness at other places. So far as the thin- 

 bedded shale can be said to have dip it seems to conform to that of the 

 Louisville limestone. If this is true the surface of the Laurel limestone, 

 on which it rests, must be irregular. The exposed Laurel limestone in the 

 bottom of Conn's Creek nearby shows that it has no appreciable dip, 

 nor has it been disturbed by an uplift. Hence it is reasonable to con- 

 clude that the irregular surface below the Waldron shale has been the 

 result of erosion which took place after the Laurel beds were deposited 

 and before the "Waldron shale came into existence. The inclined position 

 of the Louisville limestone layers is the outcome of irregularities formed 

 during sedimentation. 



The unconformities described on Flatrock Creek are minor affairs com- 

 pared with the Avery quarry locality. The horizon of the Geneva and 

 Louisville limestone unconformities change, and at one place is found be- 



