320 Dale — Drag-Folding in Alabama Marble. 



Dr. William F. Pronty^ refers to evidence of ^' drag- 

 folding" in the marble at Gantts quarry about a 

 mile S.W. of the Moretti-Harrah quarry. Drag-fold- 

 ing differs from plicated bedding in that it consists 

 of the plication of the central part of a bed only, the upper 

 and lower surfaces of which are not at all plicated. It 

 has been explained by Reusch^ as being the result of the 



No. 2. Slab of white marble (12 by 1 ft.), from the same quarry as 

 Fig. 1, showing on the sawn face, which is parallel to the dip direction, 

 lenses bounded by films of muscovite schist and also plicated schist laminae on 

 either side of it. 



unequal gliding of the upper and lowermost parts of a 

 bed under lateral compression so as to drag the next 

 adjacent parts of the bed in opposite directions and to 

 fold them. Under accompanying pressure in a direction 

 highly inclined to the bed this folding might easily pass 

 into intense plication without affecting the upper^ and 

 lower surfaces of the bed. The writer has figured such 

 intra-bedding plications in quartzose marble and mica- 

 ceous quartzite in Vermont.^ 



Some of the marble blocks at the Moretti-Harrah 

 quarry showed that the schist laminsB were not only 



^ Prouty, Wm. F., Preliminary Eeport on the crystalline and other marbles 

 of Alabama, Geol. Survey of Ala., Bull. 18, 1916, pp. 32, 35. 



^ Keusch, Hans E., Die f ossilien-fiihrenden krystallinischen Schief er von 

 Bergen in Norwegen. Authorized German translation by Eichard Baldauf, 

 Leipzig, 1883, p. 118, fig. 79. 



^ Structural details in the Green Mountain region and in Eastern New 

 York, U. S. Geol. Survey XVIth Ann. Eeport, pt. I, 1896, p. 558, fig. 83 ; also 

 in U. S. G. S. Bull. 589, The calcite marble and dolomite of Eastern Vermont, 

 1915, pp. 38, 39. 



