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Indiana University Studies 



When these occur the stone is usually rejected. The presence of 

 large fossils also causes the rejection of the stone. 



When the stone in the quarr}^ has been covered by nothing 

 but the loose material resulting from the disintegration of the 

 upper part of the formation, the stone will be traversed b}^ a 

 number of deep mud seams ranging up to 10 feet wide and 25 

 feet deep. These seams are the result of the action of water 

 which enters the ground and, becoming charged with the organic 

 acids of the soil and the carbonic acid gas of the air and soil, 

 dissolves the limestone along the natural joints of the rock forma- 

 tion and the connecting material from between the grains for some 

 distance into the blocks. These seams may be developed in either 

 direction, depending on the direction of the surface drainage at 

 the given point. In many of the quarries where the surface 

 drainage has been at an angle with both sets of seams it will be 

 found that both sets are developed. The most of the quarry 

 openings have been made along the edge of the outcrop of the 

 overlying Mitchell limestone and then the quarry is worked back 

 under the Mitchell stone. In such cases the seams will be less 

 enlarged, and the thicker the overburden the fewer will be the 

 number of mud seams and the less open will they be. All stone 

 formations contain joints, but the stone of this district is especially 

 free from them and large blocks can be quarried in many of the 

 quarries. 



The overburden in the quarry usually consists of a few feet of 

 loose material resulting from the disintegration of the rock strata 

 at that point, and the overlying limestone of the Mitchell forma- 

 tion. When this limestone layer is lacking, the amount of waste 

 due to weathering of the building-stone layer is greatly increased, 

 and, in fact, the amount of waste resulting from the fact that the 

 stone has no good cover may make it unprofitable to operate 

 such a quarry. The result of thick stripping of the underlying 

 stone is very noticeable in such quarries as the old P. M. and B. 

 quarrj^ operated by the Indiana Quarries Company and the 

 George Doyle quarry in Dark Hoilow where upwards of 30 feet 

 of Mitchell limestone is removed. In these quarries the seams are 

 hardly noticeable, and none of the joints has been opened and 

 filled with mud as is the case in many quarries where little rock 

 stripping is necessary. 



In many of the quarries there occur structural irregularities 

 known as stylolites, usually called ''crowfeet" or ''toe-nails". 

 These irregularities are^^the only representatives of bedding 



