Stockdale: Stylolites 



25 



pression of sediments while in the soft plastic state — has been 

 offered several times with various modifications. The second, 

 the "Solution Theory" — that stylolites are a result of differ- 

 ential chemical solution under pressure in hard rock — is the 

 most recent explanation and today is generally held as most 

 plausible, especially by recent German investigators. Because 

 of lack of sufficient evidence in support of them, however, 

 neither of these theories has received definite acceptance by 

 American workers. The following is a grouping of the prin- 

 cipal advocates of the two theories : 



a. Pressure Theory 



Quenstedt, 1837, 1861 

 Thurmann, 1857 

 Marsh, 1867 

 Giimbel, 1882, 1888 

 Pvothpletz, 1900 



b. Solution Theory 



Fuchs, 1894 

 Reis, 1901, 1902 

 Wagner, 1913 



Pressure Theory. Quenstedt is the originator of the 

 pressure theory, suggesting for the first time, in 1837, that 

 stylolites may have resulted from compression of plastic sedi- 

 ment. After having changed his views in 1853, when he pro- 

 posed a theory similar to the one of Plieninger, he went back 

 to his original pressure idea, in 1861, and offered a rather 

 elaborate explanation. He took the view that two beds of 

 lime ooze overlying one another, separated by a layer of 

 shells and a laj^er of clay, would be so compressed into one 

 another that stylolites would result. The two beds, at the 

 time of compression, would have different hardness becaus'^ 

 of the different times of their deposition (Quenstedt, 1861, 

 p. 200). 



Thurmann launched his pressure theory in 1857. He ad- 

 vocated the view that two lime layers lying one above the 

 other, in a plastic state, would be differentially compressed 

 into one another regardless of whether or not there were a 

 clay layer between them. He also explained the ''Gerollein- 

 driicke" of the Nagelfluh (Tertiary) as a result of pressure 

 while the pebbles were in a plastic state. 



Pressure Theorij of Marsh. Probably the most com- 

 monly accepted theory in America is that of Marsh (1867, 



