Stockdxde: Stylolites 



33 



stylolites. Mussel and brachiopod shells, and oolitic grains 

 show all stages of solution. 



6. Above the stylolite-seam, and parallel with it, the rock 

 is in an entirely undisturbed stratified position. 



7. Younger stylolites penetrate thru older ones and may 

 even eradicate them. Bent, or curved, stylolites often occui*. 

 Horizontal stylolites show no essential differences from verti- 

 cal ones. 



8. Single stylolites are not found. 



9. The size and form of stylolites depends upon the 

 nature of the rock. 



10. Direct connection between stylolites and disturbed 

 strata is observed. 



11. ''Drucksuturen" are young stylolites, or are stylolites 

 forming under changing irregular pressure. Both are form- 

 ing and "growing" today in rock strata. 



12. For the pressure theory of Quenstedt, Giimbel, and 

 Rothpletz, there appears scarcely any proof. In most cases 

 the evidence is directly opposite. The solution theory of 

 Fuchs, which Reis elaborates, always gives a satisfactory ex- 

 planation. It is experimentally confirmed. 



Other Investigations. The first to suggest that stylolites 

 may have formed in hardened rock was Cotta, in 1851. How- 

 ever, until Fuchs advanced his theory, it was generally ac- 

 cepted that they originated while the rock was in a plastic 

 state. Bittner, in 1901, came to the conclusion, as did Fuchs 

 and Reis, that the sharp distinction between stylolites and 

 "Drucksuturen", which Rothpletz made, was a faulty one. 



Grabau (1913, pp. 786-788) accepted the solution theory 

 as the most satisfactory, stating that 



ordinary pressure work has, however, not taken place here, for nowhere 

 is there any evidence of deformation of the beds by crowding- or com- 

 pression above the columns, which project from one face of the suture 

 into the hollows of the other. 



Another recent investigator to suggest the solution theory 

 as the one most plausible is Gordon (1918, Jour. Geol., pp. 

 561-569), who concluded that 



from a study of the hundreds of examples in the Tennessee marble, the 

 writer is convinced that in the main they represent fracture planes. 

 Convincing- proof of this appears in their irregularity and frequent 

 tendency to cut across the sedimentation planes obliquely or even at 



